WO1997004368A1

WO1997004368A1 - Device for positioning and securing bodies

Info

Publication number: WO1997004368A1
Application number: PCT/DE1996/001336
Authority: WO
Inventors: Frank Richter
Original assignee: Heisel, Uwe
Priority date: 1995-07-20
Filing date: 1996-07-20
Publication date: 1997-02-06

Abstract

The invention relates to a device for positioning and securing bodies by means of a plurality of elements capable of moving in a plane of reference. According to the invention the plane of reference is verified by the stator of a planar, hybrid step-by-step motor mounted on air bearings. A plurality of programme-controlled rotors mounted on air bearings may be very accurately positioned and independently moved on the plane of reference and carry positioning and securing elements that may be manually or automatically exchanged.

Description

Device for positioning and fixing bodies

DESCRIPTION

The invention relates to a device for positioning and fixing bodies according to the preamble of claim 1.

By using this device, the productivity of measuring and processing machines is improved, since set-up times are significantly reduced and changes in the clamping during the work process are possible without manual intervention. At the same time, significantly less storage space for devices and device elements is required overall.

According to DIN 6300, devices are defined as "production means which are bound to workpieces and are directly related to the work process. They serve to position, hold or clamp workpieces and, if necessary, to guide one or more workpieces ". The requirements for the construction of such devices are therefore closely linked to the work process to be carried out. Different devices are always required for different work processes to be carried out on a workpiece, since the workpiece, for example, is not equally freely accessible from all sides. These devices are therefore adapted to the geometric properties of the workpieces to be held and cannot generally be reused for parts with a different shape. Thereby Appropriate devices must be kept in stock in a special warehouse for all workpieces, which are then exchanged before a new work process or with a new workpiece. The set-up time required for this requires a standstill and thus production loss of the respective working machine.

Instead of using rigid devices which are each only adapted to one workpiece, modular device systems have been developed for different work processes. B. for milling - see BLÜCO company lettering - or for measurements on coordinate measuring machines - see KOMEG and WITTE company letters -; see also Walter Kimmelmann, Diss.RWTH Aachen, 1991). These devices are assembled on the basis of standard modules, which are then dismantled after use and used again for new devices. This reduces the number of devices and saves storage space. A decisive disadvantage of this handling, however, is the time required to assemble and disassemble the devices, and the personnel required. In practice, therefore, and also for reasons of availability, modular device systems are used to construct devices; however, these devices are each completely stored and no longer disassembled. The previously envisaged advantage is thus lost.

In order to avoid the disadvantages mentioned, flexible devices, ie devices that are adjustable in shape and arrangement, have been developed. In connection with coordinate measuring machines, an arrangement has become known in which the elements from which the overall arrangement is constructed are themselves adjusted by the measuring machine and positioned on a reference plane (cf. DE 38 03 031 Ali. This means that a large number of work pieces are clamped, but the disadvantages of the long changeover times are only inadequately remedied. The known coord iat enmeßma seh i ne must move or adjust them one after the other when using several support and holding elements. Also, in the case of the coordinate measuring machine used, a reinforced design of the high-precision axle drives and guides is necessary due to the load occurring when moving the elements. However, the said device can only be operated with a special coordinate measuring machine.

The invention is therefore based on the object of specifying a flexible device of the generic type in which the above-mentioned disadvantages Le adhering to the known devices for positioning and fixing bodies are avoided.

This object is achieved by the combination of features specified in the characterizing part of patent claim 1.

It is assumed that a planar air-bearing hybrid stepper motor is used, on the flat stator of which several air-bearing runners can be moved independently of each other in a program-controlled manner and positioned with high precision (see documentation from PASIM Mikrosystemtechni k GmbH, Suhl} The task of solving the runners is coupled with elements that can be exchanged manually or automatically, ie tensioning devices and / or supports for positioning and fixing a body.

Apart from the aforementioned concrete conception regarding the device for positioning and fixing bodies, it should be pointed out here that - starting from the known hybrid stepper motors - the present invention includes a new and not obvious use of these known hybrid stepper motors. A column perpendicular to the XY reference plane of the stator is mounted on at least one of the rotors of the hybrid stepper motors (ZR direction). Attached to this column is a part L, which can be positioned or fixed about this axis, with additional positioning and / or clamping means, by means of which a workpiece can be positioned or clamped. The part adjustable in the Z direction can be designed so that it can be adjusted automatically or manually over part of its overall length (e.g. linear unit), that it can be extended telescopically, or that it remains at a constant distance from the XY reference plane. In addition, a rotating unit can be attached to the rotor, which allows the column to be rotated manually or automatically around the Z axis. In a further embodiment, a swivel / swivel unit can be provided, by means of which the column can be manually or automatically oriented at any angle relative to the XY reference plane. Basically, a manually operated or automatically functioning locking of the turning / swiveling unit or the Z-axis adjustment device is provided. By coupling several runners with columns built on them and adjustable in the Z direction, different spatial shapes or mold cavities for holding bodies can be realized with the help of an elastic body. It is also possible to implement a positioning or tensioning device which is adjustable in the Z direction with at least two sliders coupled via fixed or adjustable bar elements.

According to a further embodiment of the invention, in addition to the ⁽ at least one) column which can be moved on the XY reference plane, at least one further column which is fixedly mounted on the stator is provided. In a further embodiment of the above-mentioned planar hybrid stepper motors and in this respect deviating from the known mode of operation, the runners with the device elements located thereon for positioning and fixing in their respective end positions are no longer air-borne, but are liable by switching off the air supply and switching off of the motor current with a high, area-distributed permanent magnetic force on the stator plate. The runners can also absorb machining or process forces.

The rotors can also be coupled by means of a gear. In this respect, tension / pressure medium gears, such as scissors and levers for strengthening or weakening adjustment paths and forces, are intended, by means of which workpieces can then be clamped or positioned.

In a further embodiment of the invention, the stator plate is arranged to be rotatable about an axis lying parallel to the XY reference plane. This makes it possible to swivel the device for positioning and fixing bodies out of the horizontal or to rotate it through 180 degrees, e.g. to be able to remove chips that arise during machining processes more easily. Due to the high magnetic forces that can be activated in their end position with respect to the rotor (perpendicular to the XY reference plane), it is possible to reverse the stator plate, i.e. with the tread downwards, so that workpieces can be clamped over head.

The runners can have different sizes in order to achieve different holding forces when moving or stretching the body. Sensors for measuring the occurring forces and moments can also be arranged on the rotors, via which elastic, plastic or other non-dimensionally stable bodies by force-sensitive position control can be held and tensioned optimally and without undesired deformation. These sensory devices can also be used to tension bodies which, in order to maintain their actual installation position, their dimensions and their shape, must first be deformed accordingly. Quality controls can be carried out using force measurements.

In the end, measuring means, sensors and / or processing units can also be attached to the fixed pillars and the fastening elements mounted on the runners using appropriate tools. This makes it possible to measure or machine the clamped or positioned workpiece.

The exact position of the runners relative to one another or relative to a fixed point of the stator is exactly determined by means of suitable contacting or non-contact distance measuring systems or is calculated by the setpoint of the positions of the runners in the reference plane, which the control system specifies for the runners .

The position and / or orientation of the body inserted or tensioned in the device according to the invention can also be changed automatically with the aid of the device itself. The body will e.g. brought into a specific reference position or zero position for the subsequent measuring or machining operation. To determine the zero position, sensors and measuring means can be used which are attached to the rotors and / or at fixed points of the stator.

Complex bodies, which have undercuts, for example, can be inserted automatically or manually into the device, since the columns are automatic and can also be moved step by step. In the event that a body is not inserted directly the device moves, for example, to a preposition; the body is held in the device and then moved into its end position without collision.

The totality of the positioning and / or clamping processes can possibly be control via a central data processing unit. In this respect, it is also conceivable to program the travel and movement steps of the runners and / or the actual tensioning and support elements according to the type of the TEACH-IN method.

The advantages of the device according to the invention over all known solutions are based primarily on the elimination of set-up times. The spatial arrangement of the individual columns with the positioning and clamping devices attached to them is saved and, if required, can be called up again in the shortest possible time. Ultimately, this also eliminates expensive warehousing for complete devices.

Contrary to the device known from DE 38 03 031 A1, all columns are moved simultaneously and automatically. This significantly reduces the set-up time and the device for positioning and clamping bodies can be used on any measuring or processing machine.

With the columns that can be moved automatically in the XY reference plane, two elementary functions can generally be achieved:

First, conventional positioning or tensioning elements which are attached to the columns can be positioned, ie the columns take over the positioning function and the tensioning elements take over the tensioning function. Secondly, the columns can also be used to clamp workpieces directly (positioning and clamping). For this purpose, the clamping elements are moved into an insertion position and the part is inserted; After that, certain sliders are moved along a precisely defined path in order to apply a clamping force parallel to the XY reference plane.

The device is suitable in connection with work processes in which low process forces occur, equally for dimensionally stable and non-dimensionally stable workpieces. Work processes of this type are, on the one hand, measuring processes (tactile or non-contact detection), and on the other hand, they can also be used in machining processes and joining processes for non-ferromagnetic materials (e.g. machining processes on wood, plastics, aluminum, etc.).

As a result of the possibility of being able to move several runners simultaneously, clamped workpieces can also be moved relative to stationary measuring devices or measuring devices which are moved on other runners. This is particularly useful when optically scanning surfaces or shaped elements with the aid of line cameras, since no additional drive is required.

Since clamped bodies are generally inaccessible at their clamping and bearing surfaces, the device described can be usefully used insofar as individual columns are directly active during the working process (measurement, processing), ie program-controlled, solved, moved and on another Can be put back on the workpiece. This means that all parts of a workpiece are accessible. A particular field of application in this regard is the wood and plastic processing industry (for example furniture) in connection with the processing of small parts or workpieces. These parts can usually not be held on a vacuum plate or with vacuum clamps, as is customary when machining plate-shaped workpieces, since the effective clamping surface is too small. Mechanical clamps for clamping the parts would therefore be advantageous. However, these mechanical clamps generally stand in the way of machining, ie such a small part cannot be machined all around (frequent machining: edge machining for panels or the like) in one and the same clamping, but the clamps would have to be on in between a different position is shifted so that all locations of the part to be machined are accessible. Here, the device according to the invention offers the advantage that individual clamps could be released under computer control during processing and moved out of the processing path. Then they could be moved back into the old clamping position, and it would only have to be ensured with this procedure that there are always enough clamping elements on the workpiece. The clamping elements could be "automatically" removed from the processing path during processing or during operation with the aid of sensors on the clamping elements themselves or on the processing tool by generating a corresponding signal for controlling the clamping device.

It would also be conceivable to enter all movements of the clamping elements before starting machining in the manner of the "teach-in method", but this would require a high level of programming. Complex bodies can generally not be placed in a clamping device in a self-contained process, but are first placed in a position in which certain clamping elements are then adjusted; inaccessible parts of the edition are also reached in this preposition. The workpiece is then gradually brought to its end position. In order to automate this process, the device elements must each be capable of being moved independently. This is not possible, for example, with the device known from DE 38 03 031 A1. A body in the device can be brought into a “zero position” or a reference position by a program-controlled method of the individual device elements. This eliminates the steps "probing" and "measuring the actual position", as well as "arithmetic referencing" and subsequent "orientation of the body", which precede the actual work step when measuring or processing. This minimizes additional idle times that lead to poor utilization of the measuring or processing machine.

The invention is explained below with reference to the drawing. This shows in

1 shows a principle of a first embodiment of a device for positioning and fixing bodies in supervision;

FIG. 2 shows a basic illustration of a second exemplary embodiment of the device according to FIG. 1 in side view and in top view;

Fig. 3 is a schematic representation of a third embodiment of the device according to claim 1 in side view and in supervision.

1 shows a three-dimensional view of a first embodiment of a device for positioning and tensioning bodies, the base of which is known from a known planar air stored hybrid stepper motor is formed. A stationary stator plate 1 of this hybrid motor, which serves as an XY reference plane for positioning elements 2, 3 and 4, is assigned two different rotors 5, 6, which - in particular program-controlled - on an air bearing between the underside of the rotor and the Stator plate 1 can be moved. The supply voltage, the control signals and the required compressed air for the two rotors 5, 6 are transmitted via energy chains 7 from the stator plate 1 to the rotors 5, 6. On the two rotors 5 and 6, as well as on the side of the stator plate 1 itself, adjustable fastening elements 8 are attached, which can be mounted in different positions on the respective rotors 5 and 6 or on the stator plate 1. In particular, cylindrical rods 9 are attached to these fastening elements 8, the respective position of which on the fastening elements 8 can be varied.

The rods 9 have positioning and support elements 10 on their free end faces, which e.g. are fixed with the help of a clamping mechanism. The positioning and support elements 10 are displaceable in the axial direction Z of the rods 9 and they can also be rotated about this axial direction. The positioning and support elements 10 are also provided with respectively adjustable functional elements: each a conical support element 11 and a cylindrical pin 12 can thus be moved and locked in the axial direction of the rods; In addition to these latter elements, surfaces 13 are also formed on the positioning and support elements, which are also included when positioning a body.

With the help of the device for positioning and tensioning bodies shown and described so far, bodies of any shape can be made relative to a - not shown - position and clamp the processing machine. The rotors 5, 6 can be moved or displaced freely in the XY reference plane of the stator plate 1. Fastening elements 8 are in turn variably fixable on the upper sides of the runners 5, 6; these fastening elements 8 also have rods 9, on which positioning and positioning elements 10 which are adjustable or movable in the Z direction are arranged.

A device for positioning and tensioning bodies is thus available, with which even a complex body can be grasped and supported at various fixed or support points. The runners 5, 6 can be moved with a central data processing device 100, which can be programmed according to the type of TEACH-IN method. It is also conceivable to include the positioning and support elements 10 or their elements conical support element 11, cylinder support 12, base area 13 in the program-controlled control.

Fig. 2 shows a side view and a top view of a second embodiment of the device for positioning and tensioning bodies with various positioning and tensioning elements. The stator plate 14 is mounted on a base frame 15 on which the fixed positioning and tensioning elements 16 are also mounted. The runners 17 are of different sizes and both on the fixed columns 16 and on the column l δ which can be moved via the runners 17, clamping elements 19 and positional elements 20 are attached, which are fixed - cf. Reference numerals 21 -, or adjustable in the Z direction and / or designed to be rotatable about the Z axis.

Fig. 3 shows schematically in side view and in supervision a third embodiment of the positioning device and stretching bodies. X) The stator plate 14 is also mounted here on a base frame 15 on which the fixed positioning and clamping elements 16 are arranged. The runners 17 used are of different sizes and clamping elements 19 are attached to the fixed columns 16. In this particular embodiment, the automatic adjustment of the positioning and tensioning elements in the Z-axis is achieved by coupling two barrels M7 by means of a coupling gear 22 and by changing the distance between the two runners 17. For this purpose, the handlebars of the coupling gear 22 are rotatably mounted on the rotors 17.

Claims

Device for positioning and fixing bodiesP ATENT REQUESTS

1. Device for positioning and fixing bodies with the aid of a plurality of elements which can be displaced on a reference plane, characterized in that the reference plane is verified by the stator of a planar, air-cooled hybrid stepping motor, and that a plurality of on the reference plane air-supported runners which can be moved independently of each other under program control and can be positioned with high precision are provided, which, if necessary, carry manually or automatically interchangeable elements for positioning and fixing.

2. Device according to claim 1, characterized in that the elements for positioning and fixing have clamping devices and / or supports.

3. Apparatus according to claim 1 or 2, characterized in that the elements for positioning and fixing are rotatably and / or pivotally mounted.

4. Apparatus according to claim 1 or 2 or 3, characterized in that the elements for positioning and fixing are formed adjustable in length.

5. Device according to one of claims 1 to 4, characterized in that at least one fixed to the stator support or tensioning device is provided.

6. Device according to one of claims 1 to 5, characterized in that the air position and rotor in their respective end position can be firmly coupled to the stator.

7. Device according to one of claims 1 to 6, characterized in that the Luftge l age rt en rotor have additional transmission means, via which a specific influencing of clamping forces can be achieved.

8. Device according to one of claims 1 to 7, characterized in that the stator forming the reference plane is designed to be rotatable and / or pivotable.

9. Device according to one of claims 1 to 8, characterized in that the runners have sensors and actuators via which the positioned and fixed body can be measured and optionally processed in a targeted manner.

10. Device according to one of claims 1 to 9, characterized in that a central data processing device is provided, by means of which the runner with the elements for positioning and fixing can, if necessary, be brought into their predetermined positions on the reference level on the basis of a TEACH-IN programming.

11. The device according to claim 10, characterized in that the runners with the elements for positioning and fixing during a machining process temporarily released and ver¬ can be brought out of the machining path of the tool, so that each point of the workpiece to be machined can be machined.

12. Use of a hybrid stepper motor with a stationary stator and a plurality of air-bearing movable rotors as the base unit of a device for positioning and tensioning bodies, the runners on the one hand carrying predetermined tensioning and positioning elements according to the respective body and on the other hand relative to Bodies, in particular program-controlled, can be moved freely at the same time.