The invention is particularly intended for machining material that can be moved by means of an arrangement along a production line and into the vicinity of mechanical tools positioned in respective stations along said production line, said production line having the form of a supporting surface, or for machining material with the aid of machine tools that can be moved along said production line by means of such an arrangement.

These arrangements are adapted to be moved and/or displaced across and along a supporting surface of the production line, with the aid of an air cushion and/or movement generating means.

The present invention also relates to an arrangement that can be moved and/or displaced along and across a supporting surface, and more particularly to such an arrangement that can be moved rapidly or displaced slowly across a planar supporting surface, wherewith the position of said arrangement can be evaluated in computer equipment, and wherewith movement from one position to another can be controlled by computer equipment.

The arrangement according to the invention has a bottom part, a top part, and an inner part, wherewith the bottom part is adapted for frictionless movement over the supporting surface through the medium of an air cushion applied beneath the undersurface of the bottom part and said supporting surface and exerting a lifting force on said bottom part. The bottom part, however, can be held firmly to the supporting surface in a selected positional setting, by at least removing the lifting effect of the air cushion.

DESCRIPTION OF THE BACKGROUND ART Systems of the kind described in the introduction and utilising an arrangement which can be moved and/or displaced along and across a supporting surface are known to the art.

These arrangements are adapted to move quickly or to be displaced slowly over a planar supporting surface, where the position of said arrangements can be evaluated in computer equipment, and where movement of an arrangement from one position to another can be controlled from said computer equipment.

Systems are also known in which the arrangements used include a bottom part, a top part and an inner part, where the bottom part can be moved frictionless over the supporting surface, through the medium of an air cushion applied beneath the undersurface of the bottom part and said supporting surface and exerting a lifting force on said undersurface. The arrangements, however, can be held firmly to the supporting surface in a chosen positional setting, by at least removing the lifting effect of the air cushion.

It can be mentioned by way of example in this respect that Patent Publication US-A-4,192,240 teaches a machine tool which includes a support means for holding a workpiece and a table having a support surface for supporting said support means.

The table surface includes a plurality of openings through which air can be passed to and removed from a space between the support means and the table.

An operator-controlled valve functions to either connect selectively an air source to said openings such as to generate an air cushion which allows the support means to be positioned relative to the table in a frictionless or friction-free manner, or connect a vacuum source to said openings such as to apply a holding force which holds the support means in a fixed position relative to the table.

The force at which the support means is held against the supporting surface can thus be amplified by applying a subpressure between the undersurface of the bottom part and the supporting surface.

SUMMARY OF THE INVENTION TECHNICAL PROBLEMS When taking into consideration the technical deliberations that a person skilled in this particular art must make in order to provide a solution to one or more technical problems that he/she encounters, it will be seen that on the one hand

it is necessary initially to realise the measures and/or the sequence of measures that must be undertaken to this end, and on the other hand to realise which means is/are required in solving one or more of said problems. On this basis, it will be evident that the technical problems listed below are highly relevant to the development of the present invention.

When considering the present state of the art, as described above, it will be evident that a technical problem resides in creating, with the aid of simple means, conditions whereby a system of the aforementioned kind is able readily to form a planar supporting surface which extends along a desired production line and which passes through one or more material working stations.

Another technical problem is one of creating, with simple means, conditions which will enable a necessary planar supporting surface to be formed by a plurality of mutually adjacent sections of said supporting surface, these sections being referred to hereinafter as supportive sections.

Another technical problem is one of realising the significance of positioning said supportive sections in edge- to-edge relationship.

Another technical problem resides in realising the significance of providing a system that is so structured that at least each of a chosen number of supportive sections used will include points and/or elements that function to register the arrangement relative to the supporting surface, with a predetermined distance between selected points and/or elements.

Another technical problem is one of creating readily conditions where a chosen distance between edge-related points and/or elements on a first supportive section and edge-related points on a second supportive section will be the same as the distance between registering points and/or elements on the supportive section in general.

Another technical problem is one of realising the significance of and the advantages that are afforded by allowing edge-related points in such a system to be orientated in the edge part of respective supportive sections, and also to realise that said edge-related points will preferably be orientated between 0 and half the distance between the chosen registering points on the supporting surface in general.

Another technical problem is one of realising the significance of and the advantages that are afforded by allowing one or more supportive sections to be adapted for coaction with means for lifting a supportive section and with means for lowering said supportive section.

Another technical problem is one of providing, with the aid of simple means, conditions such that said lifting means or said lowering means shall be adapted for lifting one or more supportive sections vertically from a first horizontal production line to another horizontal production line, with one or more arrangements resting thereon.

Another technical problem is one of creating and using such an arrangement in a system of the aforedescribed kind, where said arrangement is adapted for movement quickly from a first

chosen position related to a first registering point or several registering points, to another chosen position related to a second registering point or several registering points, and therewith allow the arrangement to be displaced to a predetermined, exact position when required.

Another technical problem is one of realising the advantages that are afforded when said arrangement is connected over a conductor to a rail arrangement along which said conductor can be moved and to which rail arrangement computer equipment is connected via a drive circuit, and also the need for such connection.

A technical insight is required to realise that the computer equipment shall be programmed not only to control movement and/or displacement of the arrangement, but also to control means with which the arrangement can be held firmly against a supportive section, to activate machine tools when required, or to activate material at respective material working stations.

Another technical problem is one of realising that in the case of a system of the aforedescribed kind, said arrangement shall include means that functions to hold said arrangement against a chosen supportive section and that coacts with an inner part of said arrangement, said holding means being adapted to fixate said inner part relative to said supportive section, wherewith a bottom part and a top part of said arrangement shall be capable of being moved relative to said inner part through the medium of movement generating means mounted in said bottom and top parts of the arrangement.

Another technical problem is one of realising the advantages that can be gained where each supportive section is provided with a plurality of registering elements orientated in rows and columns, and when respective supportive sections are mutually identical.

Another technical problem is one of realising that said elements may comprise pins which are spaced apart at a distance corresponding to the distance between registering elements in the supportive section, or vice versa, so as to obtain accurate movement and displacement of said arrangement.

With respect to making the system more effective in accordance with the invention, it will be seen that a technical problem is one of realising the significance of allowing the movement path of said bottom and top parts in relation to said inner part to slightly exceed a chosen distance between registering elements.

It will also be seen that a technical problem resides in realising the significance of and the advantages that are afforded by allowing an arrangement to be moved along a supportive section by a) activating the holding means such as to fixate the inner part of an arrangement relative to said supportive section; b) applying an air cushion beneath the undersurface of the arrangement;

c) displacing the arrangement relative to said supportive section with the aid of movement generating means included in said arrangement; and d) removing the air cushion at a predetermined position, such as to bring the bottom part into fixed relationship with the supporting surface.

Another technical problem is one of realising the advantages that can be gained by allowing said holding means to be deactivated at a fixating position according to d, and to allow said holding means to be moved within the arrangement to a predetermined position with the aid of movement generating means, where said determined position may be a new registered position.

Another technical problem is one of providing in such an arrangement with the aid of simple means conditions where means that can coact with said inner part will function to mechanically fixate said inner part relative to said supporting surface or to release said inner part relative to said supporting surface.

In an arrangement of the kind described in the introduction, a technical problem also resides in allowing the bottom part and the top part of the arrangement to be immovable relative to one another, while also realising that these two parts may be movably arranged relative to said inner part and moved by means of movement generating means.

Another technical problem is one of providing a construction that will enable all movement generating means to be

incorporated within the bottom and top parts of the arrangement, and also to enable the inner part to be incorporated./ ?/ Another technical problem is one of enabling the movement generating means, in the form of stepping motors or the like, to be computer controlled such that a chosen point or corresponding point on the upper surface of the top part of the arrangement can be moved to a predetermined position in a coordinate system, such as a right-angled coordinate system, which is also referred to a fixation point on the supporting surface.

Another technical problem is one of realising that the active surface of the chosen point can be increased by a combination of linear movement and rotary movement, and the accuracy that is achieved thereby.

Another technical problem is one of realising the significance of and the advantages that are gained by providing the air-cushion accommodating surface of the bottom part of the arrangement with an inner aperture through which said holding means can be moved to a position in which it is fixedly related to the supporting surface and functions as a fixation point, or to a position in which the arrangement is released from said supporting surface.

It will also be seen that a technical problem resides in realising the significance of and the control simplifications that are achieved by allowing each fixed related position between the holding means and the supporting surface to

comprise a registered or fixed position that can be evaluated by and stored in said computer equipment.

Another technical problem is one of realising the significance of providing a support plate forming said supporting surface with a plurality of registering elements orientated in mutually perpendicular rows and columns and adapted for precise coaction with said holding means.

Another technical problem resides in realising the significance of providing said holding means in the form of two pins that are spaced horizontally apart at a distance which corresponds precisely to the distance between two position fixing holes in the supporting surface, or vice versa.

Another technical problem is one of realising the significance of and the advantages that are gained when the linear movement path of said bottom and top parts of the arrangement relative to the inner part thereof exceeds the horizontal distance between said registering elements, said parts being moved through the medium of movement generating means.

It will also be seen that in the case of an arrangement of the aforedescribed kind, a technical problem resides in realising the significance of and the advantages that are gained by enabling said holding means to be rotated relative to said inner part with the aid of movement generating means.

It is proposed in this respect that said holding means shall coact with a gear ring that, in turn, coacts with a motor- driven gearwheel or pinion.

A particular technical problem resides in realising the significance of rotatably mounting said inner part and said holding means on an inner plate and to rotate said inner part and said holding means with the aid of movement generating means, and to enable said plate to be moved linearly and reciprocatingly in parallel with said supporting surface, with the aid of movement generating means.

The linear movement generating means may comprise a screw- threaded rod that can be rotated by a motor-driven wheel or shaft.

Another technical problem is one of supporting the inner plate in said inner part on wheels or corresponding friction- reducing means and controlling said plate for linear forward and backward movement.

Another technical problem is one of realising the significance of enabling the upper part of a movement generating means to be rotatable relative to the inner plate.

Another technical problem is one of creating conditions for a method for not only displacing but also moving an arrangement along a supporting surface, by a) activating a holding means so as to fix the position of the inner part relative to the supporting surface;

b) applying an air cushion between an undersurface of a bottom part and said supporting surface; c) activating one or more movement generating means such as to move or displace the top and/or the bottom parts of the arrangement relative to the supporting surface, such that a point or the like on the uppermost surface of the top part will be moved to a predetermined position in a coordinate system; and d) removing the air cushion when said predetermined position is reached, so that the bottom part will be fixed in relation to the supporting surface.

Another technical problem resides in deactivating said holding means in a fixed position of said bottom part according to d) above and with the linear movement at one end position or essentially in one end position, and in moving or displacing said bottom part towards a predetermined second end position or the like with the aid of the linear movement generating means, and thereafter activate said holding means in this latter position as a new fixed position.

It is particularly proposed that each of said determined positions will be a registered position with mutual coaction between said holding means and said supporting surface.

SOLUTION With the intention of solving one or more of the aforesaid technical problems, the present invention takes as its starting point a system for either machining in one or more working stations material that can be moved along a production line formed as a supporting surface with the aid of machine tools in respective stations, or for working material positioned in the production line with the aid of machine tools that can be moved along said production line, wherewith said movement can be effected with the aid of one or more arrangements that can be moved and/or displaced along/across a supporting surface in said production line through the medium of an air cushion and/or movement generating means.

In such a system, it is proposed in accordance with the invention that at least a part of said supporting surface shall be formed by a plurality of supportive sections positioned in edge-to-edge relationship, that each of these supportive sections shall include a plurality of points and/or elements that register the arrangement in relation to the supporting surface, wherein said points/or elements are spaced at a predetermined distance apart, and that a chosen distance between edge-related points and/or elements on a first supportive section and edge-related points on a second supportive section will be equal to the distance between registering points and/or elements on a supportive section in general.

By way of preferred embodiments that lie within the scope of the inventive concept, it is proposed that the edge-related

points on a supportive section shall be orientated between 0 and half the distance between registering points on the supportive section in general.

It is also proposed that the supportive sections are able to be moved laterally in relation to each other when the need arises.

It is also proposed in accordance with the invention that one or more of these supportive sections included in said production line is/are adapted for coaction with means for lifting a respective supportive section or with means for lowering said supportive section.

It is also proposed that the section lifting means or the section lowering means are adapted to move a chosen supportive section from one production line to another with one or more arrangements resting thereon.

The invention also proposes the use of a system-associated arrangement that can be moved quickly from a first chosen position related to the first registering point or to several registering points to a second chosen position related to a second registering point or to several registering points, and to move the arrangement to a predetermined position when necessary.

It is also proposed in accordance with the invention that the arrangement shall be connected via a conductor to a rail arrangement along which said conductor can move and to which a computer equipment is connected via a drive circuit.

According to the invention, the computer equipment is programmed for controlling movement and/or displacement of the arrangement.

The computer equipment is also programmed to cause the arrangement to be held firmly against a supportive section, and to activate machine tools or the like in respective working stations as required.

The system-associated arrangement also includes means for holding said arrangement firmly to a selected supportive section and for coaction with an inner part of said arrangement, wherein said holding means is arranged to fixate said inner part relative to said supportive section, and that said arrangement also includes a bottom part and a top part which can be moved relative to said inner part with the aid of movement generating means mounted in said bottom and top parts of the arrangement.

It has been found particularly beneficial to provide each supportive section with registering elements arranged in rows and columns.

According to the invention, said holding means may comprise pins which are spaced apart at a distance that corresponds to the distance between registering elements in the supportive section, or vice versa.

In the inventive system, the movement path travelled by said bottom and top parts of the arrangement relative to its inner part is caused to exceed slightly a chosen distance between

registering elements, wherein said holding means may be rotatable relative to said inner part.

The system is also based on allowing an arrangement to be moved along a supportive section by a) activating the holding means so as to fixate the inner part of said arrangement relative to said supportive section; b) applying an air cushion beneath the bottom part of said arrangement; c) displacing the top and/or bottom part of the arrangement relative to said supportive section with the aid of movement generating means belonging to said arrangement; and d) removing the air cushion when a predetermined position is reached, so as to cause the bottom part of the arrangement to be fixed relative to said supportive section.

In said fixed position according to d), the computer equipment deactivates said holding means, so as to release said arrangement from the supportive section and therewith enable the arrangement to be moved to a predetermined position with the aid of movement generating means provided in said arrangement, said predetermined position conveniently being a new registered position. With the intention of solving one or more of the aforesaid technical problems, the present invention also takes as its starting point an arrangement which is moveable or displaceable along a supporting surface and which can be considered to comprise a bottom part, a top part and an inner part.

The bottom part of the arrangement can be moved or displaced over the surface with the aid of an air cushion applied between the undersurface of the bottom part and said supporting surface and exerting a lifting force on said bottom part, and can be held firmly against said supporting surface in a chosen positional setting, by at least removing the lifting effect of said air cushion.

It is proposed in accordance with the present invention that such arrangement will include a holding means which coacts with said inner part so as to enable said inner part to be fixed in a positional setting, an activated position, relative to said supporting surface, and that said bottom and top parts can be moved relative to said inner part with the aid of movement generating means mounted within said bottom and top parts.

By way of proposed embodiments that lie within the scope of the present invention, it is also proposed that the air- cushion accommodating undersurface of said bottom part shall include an inner aperture through which said holding means can be moved between a position in which the arrangement is fixed to the supporting surface and a position in which the arrangement is released from said supporting surface.

It is particularly proposed in accordance with the invention that the support plate is provided with registering elements arranged in rows and columns.

It is also proposed that said holding means is comprised of two pins that are spaced horizontally apart by a distance

that corresponds to the horizontal distance between holes formed in the supporting surface, or vice versa.

It is particularly proposed that the path of linear movement of said bottom and top parts of the arrangement relative to its inner part will be slightly greater than a chosen horizontal distance between mutually adjacent registering elements.

In one embodiment of the invention, the holding means can be rotated relative to said inner part with the aid of movement generating means, for instance by causing said holding means to coact with a gear ring which, in turn, coacts with a motor-driven gearwheel or pinion.

In another embodiment of the invention, the holding means is rotatably mounted on an inner plate which can be caused to move linearly and parallel with said supporting surface by means of a linear movement generating means.

The movement generating means may be a rotatable drive screw.

According to the invention, the inner plate may be supported on wheels, on runners or equivalent low friction means for rectilinear, reciprocating movement.

According to the invention, the top part may be rotatably related to the inner plate via said bottom part.

The present invention also provides a method of moving an arrangement along a supporting surface, by

a) activating a holding means such as to fixate an inner part of the arrangement relative to the supporting surface; b) applying an air cushion beneath a bottom part of the arrangement; c) moving the top and/or the bottom part of the arrangement relative to the supporting surface through the medium of movement generating means; and d) removing the air cushion when a predetermined position is reached, such that said bottom part will be fixed relative to the supporting surface.

It is also proposed that said holding means according to a) can be deactivated and the arrangement held to the supporting surface solely by frictional contact between the bottom part of said arrangement and said supporting surface.

It is also proposed that said holding means is deactivated in the fixed position according to d) and that said holding means is displaced to a predetermined position by one or more of said movement generating means.

It is particularly proposed that said predetermined position is a registered position.

ADVANTAGES Those advantages primarily significant of an inventive system reside in the provision of conditions which enable a production line adapted to include one or more material

working stations to be readily constructed, by building the supporting surface of the production line from a plurality of supportive sections positioned in edge-to-edge relationship.

Each of the supportive sections conveniently includes a plurality of points and/or elements that register one or more arrangements in relation to the supporting surface.

The invention also enables the arrangement to be moved and/or displaced over the supportive sections of said production line with the aid of an air cushion and/or movement generating means.

Those advantages primarily achieved with an inventive arrangement that can be moved along and across a supporting surface reside in the possibilities of enabling an upper part and a bottom part of the arrangement to be moved or displaced readily in relation to an inner part thereof, thereby to bring the upper part and a point related thereto to a predetermined positional setting and there effect said movement with the aid of an air cushion that functions to lift said bottom part away from the supporting surface. The arrangement can be held firmly to the supporting surface with the aid of holding means that can coact with said inner part and that are adapted to fixate said inner part in relation to said supporting surface, in addition to causing said bottom part to be held against said supporting surface by removing the air cushion.

This creates conditions which enable a point on the upper part of the arrangement to be displaced to a chosen positional setting in a coordinate system with great precision.

The primary characteristic features of an inventive system are set forth in the characterising clause of the accompanying Claim 1 and the primary characteristic features of an inventive arrangement are set forth in the characterising clause of accompanying Claim 18.

BRIEF DESCRIPTION OF THE DRAWINGS An inventive system will now be described in more detail with reference to a preferred embodiment thereof which is adapted to work material mechanically in one or more stations along a production line in the form of a supporting surface, and to a proposed arrangement, and with reference to the accompanying drawings, in which Figure 1 is a perspective view of one embodiment of the inventive concept for application in a production line comprised of a plurality of supportive surface sections positioned edge-to-edge with solely one material working station; Figure 2 illustrates a proposed orientation of edge-related points for an arrangement used in said production line;

Figure 3 illustrates an alternative embodiment with respect to the orientation of said edge-related points; Figure 4 is a sectional view illustrating the principle construction of the lower part of an arrangement, and also shows a holding means in registered coaction with two points registering a supporting surface section; Figure 5 is a perspective view of a supporting surface along or across which an arrangement can be moved or displaced in accordance with the invention through the medium of computer controlled movement generating means belonging to said arrangement; Figure 6 is a sectioned side view of an inventive arrangement; Figure 7 is a partially sectioned view of the arrangement shown in Figure 6, seen from above; and Figure 8 illustrates an example of a movement pattern that can be obtained with the aid of three movement generating means incorporated in the arrangement.

DESCRIPTION OF EMBODIMENTS AT PRESENT PREFERRED Figure 1 thus shows in perspective a system S for mechanically working material 2'in one or more working stations along a production line A formed as a supporting surface, such as in the illustrated station S1.

The system is based on the use of an arrangement 2 which can be moved and/or displaced along and across sections of the supporting surface, of which sections some have been referenced A1.. A7 and are positioned in a consecutive order.

The arrangement 2 may be any arrangement that is adapted for movement along a supporting surface, although it may alternatively comprise an arrangement of the kind described hereinafter in more detail with reference to the drawings.

The invention is based on enabling material that can be moved along the production line A and placed on or fastened to said arrangement 2 to be worked by machines or tools belonging to a particular station, such as a drilling machine in the station S1.

Alternatively, material orientated along the production line can be machined or worked by one or more machines or tools that can be moved along said production line and that are fixed to or mounted on one or more of said arrangements 2.

For the sake of simplicity, the invention will be described in more detail with respect to material 2'fastened to an arrangement 2 and provided with a hole in the material working station S1 and comprising a drilling machine.

It is assumed that the arrangement 2 and the material 2'are both in registered positions at point P1. By registered positions is meant a chosen orientation and position.

Thus, the material 2'is moved towards the station S1 in said system by means of an arrangement 2. This arrangement can be

moved and/or displaced along a supporting surface in said production line, through the medium of an air cushion and/or movement generating means.

The supporting surface is referenced 1 in the drawings and is comprised of a plurality of surface sections, A1, A2-A7 disposed in edge-to-edge relationship.

Each of these sections includes a plurality of points la, lb that register the position of the arrangement relative to the supporting surface, and/or elements that have a predetermined distance between selected points, and/or elements where the distance is referenced d.

Although not shown for the sake of clarity, such registration points will be situated beneath the arrangement 2 at point P1.

The inventive system is based on the concept that a chosen distance between edge-related points and/or elements lla with respect to a first supportive section A1 and edge-related points llb with respect to a second supportive section A2 shall be equal to the distance d between said registration points and/or elements la, lb allocated to a supportive section A1 in general.

In the illustrated case, at least one of said edge-related points lla is positioned between 0 and half the distance between the registration points la, lb associated with the supportive section A1.

As shown in Figure 1, edge-related points lla may also be orientated in respective edge parts of the supporting surface.

In the case illustrated in Figure 2, the predetermined distance-a-is the same in the x and y coordinates of a right-angled coordinate system.

Figure 2 is intended to show that the distance between edge- related points lla, llb and the edge surface A1'is equal to half the distance between the registration points la, lb on the upper surface of the supportive section A1.

Figure 3 shows that the distance-a-between the edge-related points lla, llb is 45 degrees relative to the x and y axes of a right-angled coordinate system.

As will be seen from Figure 1, one or more supportive sections, in Figure 1 the supportive section A6, is/are adapted for coaction with a means that functions to lift said supportive section.

Means of the kind to which the invention relates are well known within this particular technical field, and consequently said means has been identified schematically solely by the reference M1.

One or more sections of the supporting surface, for instance section A6, may also be adapted to coact with supportive section lowering means M2.

As indicated and shown in Figure 1, said means Ml and M2 respectively shall be adapted for movement of said supportive section A6 from one horizontal production line A to another horizontal production line A'that is slightly above the production line A.

This supportive section A6 shall then be moved with one or more arrangements resting thereon.

The arrangement 2 includes means 40 for enabling the arrangement to be moved quickly from a first chosen position P1 relative to a first registration point or several first registration points, to a second chosen position P2 relative to a second registration point or to several registration points, and therewith, when required, move or displace the arrangement 2 towards a predetermined position with the aid of movement generating means 30,40.

The first position Pl is shown in Figure 1 with an arrangement 2, while a second position P2 is shown in the absence of such an arrangement 2.

It will be evident, however, that when the arrangement 2 is moved to the second registration point P2, a drilling machine in the station S1 will be able to drill a hole in the material 2'at a predetermined, precise position.

As will also be seen from Figure 1, the arrangement 2 is connected via a cable F with a rail arrangement F1 along which the arrangement can be moved and to which said computer equipment D is connected over a drive circuit E by means of a cable F'.

The rail arrangement F1 is shown to extend along the production line A.

The computer equipment D is programmed to control movement and/or displacement of the arrangement 2 from the first position P1 to the second position P2, and also to control affixation of the arrangement 2 to a supportive section and, when required, to activate machine tools in different stations Sl or the like at each material working station.

The system utilises an arrangement which includes means 20 for holding the arrangement against a selected supportive section and for coaction with an inner part 2c of said arrangement, wherewith said holding means 20 functions to enable said inner part 2c to be affixed relative to said supportive section 1, wherein a bottom and a top part 2b of said arrangement can be moved relative to said inner part 2c by means of movement generating means 30,40 mounted within said bottom and top parts.

As shown in Figure 1, each supportive section Al, A2-A7 is provided with rows and columns of registration elements.

The holding means 20 may be comprised of pins that are spaced apart by a distance which corresponds to the distance-a- between the registration elements la, 2b in the supportive section, or vice versa.

The system requires the movement path of said bottom and top parts relative to said inner part of said arrangement to slightly exceed a chosen distance-a-between the registering elements la, lb.

The holding means 20 shall be rotatable relative to the inner part 2c of the arrangement. The inventive system also allows an arrangement 2 to be moved along a supportive section by a) activating said holding means 20 so as to affix the inner part 2c of the arrangement 2 relative to said supportive section 1; b) applying an air cushion L beneath the bottom part 2a of said arrangement 2; c) activating movement generating means 40 so as to displace the upper part 2b and/or the bottom part 2a of the arrangement relative to the supportive section 1; and d) removing the air cushion L at a predetermined position, such as to affix the bottom part 2a of the arrangement relative to said supportive section 1.

When in a fixed position according to d), the system requires deactivation of said holding means 20 such as to raise said means above the upper surface 1 of the supportive section and activation of said movement generating means 40 such as to displace said holding means 20 within said arrangement to a predetermined position.

This determined position will preferably be a new registered position.

The arrangement 2 can be moved incrementally along the supporting surface 1, by bringing the holding means 20 into

coaction with the registering elements on the supportive section in said position, activation of the air cushion L.

It should be mentioned that when the arrangement is in position P2, it is not only firmly locked through the medium of a subpressure generated between the bottom surface of the arrangement 2 and the supporting surface 1, but also by the holding means 20 in their active holding mode.

Figure 5 is a perspective view of an arrangement 2 which has the features significant to the invention and which can be moved along a supporting surface 1.

The arrangement 2 includes a bottom part 2a, a top part 2b and an inner part 2c, this inner part being obscured in Figure 1.

Figure 6 shows the bottom part 2a and the top part 2b as a one-piece structure, although it will be understood that the top part 2b may be a separate unit which is fastened to the bottom part 2a in some convenient and known manner.

The uppermost surface 2b'of the top part 2b includes channels 2b"by means of which material to be worked or a machine tool can be held firmly on said arrangement.

The bottom part 2a of said arrangement is adapted to move across the supporting surface 1 in the absence of friction in a known manner. This is achieved by means of an air cushion L generated between the undersurface 2a'of the bottom part 2a and the supporting surface 1 by delivering pressurised air through a conduit L1, so that the bottom part 2a of the

arrangement, and therewith, of course, also the top part 2b and the inner part 2c thereof will be raised above said supporting surface.

The arrangement 2 can be held firmly to the supporting surface 1 in a chosen positional setting by at least removing the lifting effect of the air cushion L, wherewith the arrangement 2 will rest firmly against the supporting surface 1 under its own weight. Alternatively, instead of the air cushion, a holding subpressure can be generated via the conduit L1.

The supporting surface 1 includes registering points disposed in rows and columns in right-angled x and y coordinates, said registering points being shown in the form of circular holes of which two are referenced la and lb orientated in the x- direction.

The registering points la and lb are positioned beneath the arrangement 2, as shown in Figure 6. It should also be mentioned that corresponding registering points la and lb are shown laterally displaced in Figure 5, so as to facilitate an understanding of the present invention.

These registering points shall be comprised of elements orientated in rows and columns.

It is assumed in the illustrated embodiment that the points la, lb have the form of holes, preferably slightly conical holes, in the supporting surface 1.

It will be understood, however, that pins may be used in the supporting surface instead of holes, and that the pins can be brought to an upper position in which they coact with the arrangement 2 and to a lower position in which they connect with the supporting surface 1.

As will be seen from Figure 5, the arrangement 2 is controlled by computer equipment D whose outputs are connected to a drive circuit E and which is connected to the arrangement 2 via a cable F.

Conductors in the cable F control each of the movement generating means in the arrangement and also control the supply of air for generating said air cushion and, when applicable, a vacuum, control movement of said means to an activated (locked) or deactivated (released) position in relation to the supporting surface 1, and also to sense the instantaneous positions of the movement generating means so as to enable the position of the arrangement to be established and stored.

This is achieved by determining the registering points used and by determining the positional settings of the three movement generating means, of which one is for linear movement and the other two for circular movement.

Thus, it will be seen that for each selected point P on the upper surface 2b'of the arrangement 2, representing a workpiece or a tool, the coordinates of said points will be stored in the computer equipment D and that in order for a point P to be able to take a precise position in the coordinate system selected by said computer equipment, there

is required a predetermined position for one or more of the movement generating means and for the computer equipment to be adapted to control the movement generating means to said positions through the medium of chosen calculations.

According to the preferred embodiment, this displacement or movement is effected by three movement generating means, two such devices for rotary movement and one for linear movement as described in more detail hereinafter with reference to Figures 6 and 7.

By displacement is meant that the upper surface 2b'of the top part 2b of the arrangement is displaced relative to a fixed relationship with the supporting surface with respect to the arrangement 2 in general (the holding means are in a fixing mode with the registering elements in the supporting surface 1), whereas by moving is meant that the entire arrangement is moved along the supporting surface in the manner hereinafter described and illustrated.

Figure 6 shows the arrangement 2 provided with holding means 20 which coact with the inner part 2c and which can be moved to an active position in which the inner part 2c is affixed and registered relative to the supporting surface 1.

This fixed position can be evaluated by the computer equipment D.

In the illustrated embodiment, the holding means 20 has the form of two pins 21a, 21b, where the horizontal distance between said pins coincides with the horizontal distance

between the registering points la and lb in the x-direction, and also between the registering points la and lc.

Although not shown, means are included for moving the pins 21a, 21b into a lower position in which they coact with the supporting surface 1, and an upper position in which the pins are raised above the supporting surface and therewith release the arrangement from said surface.

The bottom part 2a and the top part 2b of said arrangement are arranged for rotational movement relative to said inner part 2c, through the medium of two separate movement generating means mounted within said bottom and top parts.

This will be described in more detail in the following text.

The bottom part 2a of the arrangement includes a circular, air cushion accommodating undersurface 2a'which is delimited by elastic strips 22a, 22b which are also circular in shape and therewith enclose an inner, circular aperture 23 through which said holding means 20 can be moved.

A selected linear movement path of said bottom and top parts 2a, 2b relative to said inner part 2c is adapted to correspond to and to at least partially exceed a selected distance between two mutually adjacent registering points, such as points la and lb.

The holding means 20 is rotatable in relation to said inner part 2c through the medium of a movement generating means 30 which in the illustrated case has the form of a stepping

motor 31 whose shaft carries a gearwheel or pinion 32 that coacts with a gear ring 33.

When the stepping motor 31 is actuated in one direction with the holding means 20 in an active holding mode in connection with the supporting surface 1, the upper part 2b and the bottom part 2a of the arrangement 2 will be rotated in one direction about a rotary axis 30', while actuation of the stepping motor 31 in the opposite direction will result in rotation of said parts 2b and 2a in the opposite direction.

The holding means 20 is also rotatably mounted on a plate 24 which can be displaced by a linear movement generating means 40 for movement parallel with the supporting surface 1.

In the illustrated case, the movement generating means 40 has the form of a stepping motor 41 which coacts with a rotatable screw 42 which connects with a pin 43 which, in turn, is fixed to the plate 24.

The plate 24 may be supported on wheels, runners or some other friction reducing means and moves along guide rails 24' and 24"so as to provide linear reciprocating movement and therewith enable the rotational centre 30'to be displaced.

The upper part 2b of the arrangement is also rotatably related to the plate 1 with the aid of a movement generating means 50 in the form of a stepping motor 51, the shaft of which coacts with a gearwheel or pinion 52 and which is in gear engagement with a gear ring 53.

When the motor shaft and the gearwheel 52 are rotated in one direction, the top part 2b (and also the bottom part 2a) of said arrangement will be rotated about a rotational axis 50' in one direction, and vice versa.

The bottom part 2a and the top part 2b are both cylindrical in shape and may be rotatable relative to one another.

However, said parts are fixedly related to one another in the illustrated embodiment.

The rotational axis 50'of the top part 2b is positioned centrally.

Figure 8 shows three different movement options with respect to the top part 2b of the arrangement, in accordance with two different rotary movements and one linear movement.

Figure 8a shows the rotational option with respect to point P on the upper surface 2b'of the top part 2b, this option being provided by allowing the device 30 to be actuated in each of two directions with the holding means 20 activated.

Figure 8b shows the option provided when the movement illustrated in Figure 8a is combined with rectilinear movement of the plate 24, through the medium of the device 40.

It will be evident from this that the point P can be displaced at a maximum to point P'or P", and any position therebetween.

The movement pattern shown in Figure 8a can be combined with the movement pattern shown in Figure 8b in any desired way.

The maximum extent of movement achieved with the aid of the device 40 is shown here by the distance-a-.

Figure 8c shows a further movement pattern that can be achieved by operating the device 50, wherewith the point P can be moved to the point Pa by rotation about the rotational axis 50'.

It will be evident from Figures 8a-8c that each point P represented by material to be worked or representative of a machine tool can be selectively chosen on or at the side of the surface 2b', and that this point P can be displaced to any desired points within the movement pattern, by the movement generating means 30,40.

These movements are controlled in a known manner via the computer equipment D, and each of the movement generating means may conveniently consist of a stepping motor of known construction.

The invention also enables an arrangement 2 to be moved along the supporting surface 1 with the aid of a number of registering points, such as points la, lb and lc respectively, while using primarily the movement generating means 40, but also the means 30 and 50.

The invention also relates to a method of moving an arrangement 2 along a supporting surface 1 solely with the aid of the linear movement generating means 40.

This method is based on a starting position in which the inner plate 24 is located in a position shown on the left in Figure 6, with the pins 21a, 21b positioned immediately above the holes la, lb.

The method comprises the steps of a) activating the holding means 20 so as to bring the pins 21a, 21b into coaction with the holes la, lb and therewith fixate the arrangement 2 relative to the support surface 1 via said inner part 2c; b) applying an air cushion L between the bottom part 2a and the supporting surface 1, such as to"float"the arrangement 2; c) displacing the top and/or the bottom parts 2b, 2a of the arrangement in the axial direction through the medium of the linear movement generating means 40 and via the inner plate 24, relative to the supporting surface 1 and to the left in Figures 5 and 6; d) removing the air cushion L when reaching a predetermined position, such that the bottom part 2a will be fixed in relation to the supporting surface; e) deactivating the means 20 so that the arrangement 2 will rest against the supporting surface 1 under its own weight and/or be held against said supporting surface 1 by suction; and

f) causing the movement generating means 40 to displace the holding means 20 to a position immediately above the registering points la'and la.

The procedure can now be repeated and the arrangement therewith moved selectively across the supporting surface 1 in the x-direction.

When desiring to move the arrangement in the y-direction, the device 30 is activated so that the pins 21a, 21b in said upper pin position will rotate to the y-direction for alignment with and coaction with said holes lb, lc, whereafter the device 40 can be actuated in the aforedescribed manner.

It will be understood that the invention is not restricted to the aforedescribed and illustrated exemplifying embodiments thereof and that modifications can be made within the concept of the invention as illustrated in the accompanying Claims.