EP1329283B1 - Clamping system - Google Patents

Description

The invention relates to a clamping or gripping system with a clamping device with a large stroke, in particular for a fully automatic processing line for gripping and clamping of workpieces with different shapes and formats as well such a fixture itself (see, e.g., EP-1285730-A).

Clamping drives for driving a workpiece clamping system and Workpiece clamping systems, devices for measuring the clamping force or hydraulically driven parallel vices are known.

The previously known clamping devices or systems are characterized by the fact that they mostly only for each very limited formats and sizes of certain workpieces are suitable. Especially when used in automatic Processing lines shows that the previously known Systems a very high amount of work for pressing or Operating the jigs or systems require if the workpiece format needs to be changed. In automatic processing lines, however, it is necessary Workpieces of various shapes and formats to grab and to tense. The previously known clamping devices have a stroke that matches the format or dimension of the Workpiece adapted as close as possible to a possible to provide space-saving clamping device. Of the Workpiece format change is very high due to these characteristics time-consuming. For this purpose, the entire clamping device must be replaced become. As a result, the known clamping devices to the bottleneck in automatic processing lines, in which Workpieces of various formats used for processing and have to be stretched. With the known clamping devices is a cost-effective, automatic editing, respectively Production of small batches, where inevitably often other formats are not possible.

Based on this known prior art, it is the task the invention of finding an improvement which allows also a processing or production of series with different workpiece formats, and therefore frequently occurring Format changes when gripping and clamping the workpieces, operate cost-effectively.

The object of the invention is first of a clamping device solved according to claim 1.

The invention employs a working cylinder. This is Conveniently designed as a hydraulic or pneumatic cylinder. The working cylinder consists of a cylinder, in which the piston is guided. Pistons and cylinders are movable relative to each other when in the pressurizable Working space a correspondingly pressurized medium (Compressed air, hydraulic crude oil or the like) is promoted. In general, the arrangement is chosen so that an element of Working cylinder is designed to be stationary and the other Element of the working cylinder is movable.

According to the invention it is provided that the piston of the working cylinder stored stationary is and the working cylinder with the at least one movable Clamping jaw forms a kinematic unit.

This construction is favorable in that the cylinder in the Usually encloses the piston. In a compact design it makes sense to design the cylinder as the moving part, which slides on the piston. The movement of the cylinder is then transferred to the movable jaw and thus forms the kinematic unit.

It is advantageous that the tensioning device is a carriage guide has, on which a carriage is movably mounted and the carriage carries the movable jaw. The reliability the entire arrangement is thereby increased when the mechanical loads are optimally stored accordingly. As with the clamping device according to the invention considerable holding forces and thus to build up corresponding clamping pressures it is favorable, for the guidance of the carriage one provide own slide guide on the clamping device, and to load with the storage no other parts.

Conveniently, while the carriage as the cylinder Working cylinder designed and has a corresponding Longitudinal bore. The construction is chosen so that one do not rebuild a working cylinder to match one Clamping jaws to move, but an existing jaws optimized for optimum clamping force and span. Deviating from the other way, the invention goes from here a sled made by the incorporation of the longitudinal bore becomes the cylinder of a working cylinder and so in particular in combination with use in a hydraulic circuit has considerable advantages. The hydraulic system is easily selectable so that big strokes (corresponds to the spans) can be realized and still at each clamping point Along this way there is an enormous potential for tension the workpieces consists.

In a preferred embodiment of the invention is provided in that a cylinder guide separated from the carriage guide of the cylinder is provided on the piston. For a optimal functioning of the entire clamping device, the Of course, to a high degree of a tightness of the hydraulic or pneumatic system of the working cylinder, it is advantageous if any torsional or transverse load on the Working cylinder is avoided because these loads of the To record guides of the piston or their seals are. These are not designed for this purpose. By the Separation of the respective management tasks and their separate ones Optimization for the guidance of the sledge on the one hand and for the leadership of the piston on the other hand, according to the invention a Reliably working solution proposed.

Another variant of the invention proposes that a Parallelism or quasi-parallelism of the direction of movement the movable jaw and the direction of movement the working cylinder is provided. To build up enormous forces care must be taken that the arrangement also works reliably at high pressures and forces. A deflection of the clamping forces, for example by appropriate Wedge surfaces or lever mechanisms and so on is Although in principle possible, but can at high pressures for Self-locking lead and thus the functionality of the clamping device to destroy. But is a parallelism of the direction of movement the movable jaw and the direction of movement provided the cylinder, so is a transition of the movement the cylinder on the jaws in a simple manner possible. Under quasi - parallelism, certain angles between the understood both directions of movement, for the Functioning of the clamping device are still acceptable, ie do not lead to jamming.

It is favorable that between stationary parts and movable Parts of the clamping device Stripping elements for protection are arranged before contamination. Often the tensioning devices become in metal-cutting or abrasive applications used and it is to be paid attention that the shavings are not too disability or impairment of the operation of the Clamping device leads.

In a preferred embodiment of the invention is provided that at least one return spring is provided, the at least one movable jaw then in its starting position recovers if no pressure is applied to the cylinder is. In the passive state of the clamping device this is so relaxed and open. A change of the workpiece format is easily possible, since this is e.g. through the respective Pressure or flow rate controlled in the cylinder becomes.

There are two variants for the arrangement of the return spring at. First, it is inventively provided that the return spring arranged in the pressurizable cylinder chamber is. In another variant, which may also be is very short, it is provided that the return spring in a side facing away from the pressurization secondary space of the cylinder is located. Usually, the arrangement is "before" or "behind" the piston chosen to a corresponding one To support the return spring.

It is favorable that an abutment for the hydraulic or pneumatic drive is provided. This abutment is in a variant of the invention at one end of the body arranged. In another variant of the invention this is Abutment between the two jaws, e.g. at the fixed Piston, provided. It is both possible that the Abutment between the jaws in the open position or in the tense, collapsed position. Both variants are part of the invention.

Furthermore, the object of the invention is achieved by a Clamping or gripping system according to claim 14. By using a clamping device with large stroke for gripping and clamping the workpieces with a wide variety of Shapes and formats and the connection with a Control, it is now possible, the different workpieces within a short time to grab and stretch and within the fully automatic processing line then the Processing supply. The control of the corresponding span at the chuck and its control causes that the time for gripping and clamping the workpieces too significantly reduced in a wide variety of formats. Training the clamping device is chosen so that they is automatically controllable and is also suitable for to carry out long strokes in the shortest possible time.

The term "long strokes" is exemplary as follows Understand: In the prior art clamping devices are known, which have only one hub, which ensures that the Example bruises of the hand of the operator excluded are. That is, the position of the jaws is when inserting of the workpiece chosen so that no hand parts in the remaining Gap between workpiece and clamping jaws advised can. The stroke is only sized to the gap at the given To close the dimension.

The possible stroke according to the invention exceeds this measure at least fivefold, if not ten or fifteenfold. It is, for example, and without the invention to stipulate on it, strokes of more than 60 Millimeter to realize. Here are relatively high clamping forces from about 3 to 8 tons, preferably about 4 tons, provided.

Also, the invention also proposed clamping or Gripping system solves the task described above optimal. By arranging a possible big stroke is achieved that such a clamping or gripping system with fully automatic processing lines einseztbar is. In cooperation with the controller is achieved that the respective clamping formats the different workpieces correctly capture and the clamping or gripping system the Position the jaws at the correct size.

The invention is not dependent on the clamping device to use according to the invention, although this is very beneficial, it is also possible that others Clamping devices, for example a spindles driven Vise and the like, are used.

An advantageous development of the clamping or Gripping system is characterized by a hydraulic operable vise for gripping and clamping of workpieces is provided as a clamping device. Such a Vise in conjunction with the control also allows a very fast and safe clamping of workpieces within an automatic processing line.

Another aspect of the invention is characterized in that the spindle is driven by an electric motor. Of course, the spindle can also be driven pneumatically become. An advantageous development of the clamping or Gripping system is also characterized by the fact that the Drive motor is a servomotor.

It has also been found that it is beneficial if the Control of the clamping or gripping system according to the invention is designed such that sensors the dimensions of Workpieces detect and the control corresponding signals sends the drive of the clamping device to the clamping device to set the determined workpiece size. The sensors can be used as optical and / or electrical sensors be educated. It is also envisaged that the workpiece even at least one disk, such as a Barcode, which denotes the dimensions of the workpiece and the controller reads out these data carriers via the sensors.

A development of the invention Spann- or Gripping system is characterized by the fact that the voltage of Workpiece, in particular along the entire stroke, with a previously adjustable or selectable clamping or Pressing force occurs. Of course it is too possible, a sequence of different clamping or Specify pressure forces of the controller, then the corresponding of the selected sequence is retrievable.

It is also advantageous if a device for adjustment and monitoring the tension for the tension of the Workpiece is provided. It can be avoided that on the one hand too low a voltage for the processing of Workpiece is entered for the machining process. It but at the same time also avoids that too high clamping forces for deformation or damage of the workpiece to lead.

Another aspect of the invention is characterized in that the controller has a memory in which the values for Span, clamping force as well as the different forms and Formats of the workpieces can be stored and stored. Of course, there are also certain sequences of machining operations and from the workpieces to be machined. and storable.

In a further development of the invention Spann- or Gripping system is designed as a vice clamping device designed as a machine vice.

According to one embodiment of the invention, it is provided that the clamping device is designed as a gripping system and on Robot arms of robots is arranged. The robots can be designed both stationary and movable.

Instead of the hydraulic cylinder can also be an example electrically driven spindle be provided with the movable jaw, for example via a carriage connected is. Advantageously, this is an actuator provided for driving the spindle.

It has also been found that it is advantageous when the tensioning device characterized by the fact that as a sled trained cylinder in an elongated recess of the body is admitted.

A development of the clamping device according to the invention is characterized by a body, one at one end of the main body arranged fixed jaw, a carriage, which is held in a guide on the main body and one relative to the fixed jaw movable jaw, a Abutment at the other end of the body for a hydraulic or pneumatic drive of the movable jaw, wherein the piston is mounted stationary and the cylinder with the movable jaw forms a kinematic unit.

The clamping device according to the invention is also characterized from that a return spring is provided, the at least a movable jaw then returns to its original position, if no pressure is applied to the cylinder or no clamping force is applied to the spindle.

According to the invention, it has also been found that it is advantageous if from the clamping surfaces of the clamping device holes, for Example in installation direction from the clamping surfaces down lead, which are designed such that impurities and Cooling or rinsing fluid through these holes be blown away. For example, the hole is compressed air applied.

A development of the invention Spann- or Gripping system is characterized in that a clamping device according to one or more of the embodiments described above Part of the clamping or gripping system is.

The object of the invention is also by a method according to claim 20 for Machining workpieces with different clamping formats solved. The procedure restarts the Automate gripping or clamping process and in particular to recognize a format change during clamping independently and to master. The inventive method dissolves this task in an elegant way, especially if a clamping and gripping system as described above, which is used allowed a correspondingly large stroke. But this is the Invention not limited, it can also for other clamping systems be usable.

It should be noted that under clamping a clamping of the Workpiece is understood, which is a highly accurate machining allowed without risking that the workpiece misplaced and would lead to a processing to committee. The procedure should in particular be geared to ensuring that Tension forces are used to the machining forces to resist.

Furthermore, the invention proposes that a Clamping of the workpiece is only possible if it is confirmed that the gripping width or span the respective setpoint, based on the clamping format of the workpiece, if necessary within appropriate tolerances, corresponds. It is at the fully automatic work can not be ruled out Clamping process corresponding foreign parts between the workpiece and Jam clamping jaws. These affect the exact Positioning and secure holding. Ultimately, will the movable jaws such a fault not on the desired dimension to bring the gripping or span. Would in such pressure is put under great pressure, This can lead to damage. The proposal according to the invention should just avoid such mistakes. conveniently, is provided here with the tensioning and sliding system, that provided a monitoring of the travel of the jaws is. A travel can, for example, by volume flow measurements of the hydraulic oil in or out of the working cylinder be monitored. The supplied and discharged volume corresponds a corresponding position of the baking on the travel. But it is also with proximity switches or other electrical, optical or mechanical position scanners etc. can be used.

Fig. 1, 3

je in einer Schnittdarstellung zwei Ausführungsformen der erfindungsgemäßen Spanneinrichtung;

Fig. 2

Vorderansicht und Seitenansicht im Schnitt der erfindungsgemäßen Spanneinrichtung;

The invention will be further described by means of embodiments. Show it:

Fig. 1, 3rd

each in a sectional view of two embodiments of the clamping device according to the invention;

Fig. 2

Front view and side view in section of the clamping device according to the invention;

Fig. 1 shows a sectional view through an inventive Tensioning device. The tensioning device is used in this example provided by the illustrated vise. It is a sectional view through this Vice. The reference numeral 2 is the fixed Chuck referred. This is located in the sectional view top left. In the embodiment, this is fixed Clamping jaw 2 releasably connected to a screw, so that Also, any other form of jaws arranged on the vise can be.

The reference numeral 3 is the movable jaw referred, which also with a screw detachable is firmly connected to the movable carriage 7. With the Reference numeral 4 is the pneumatic or Hydraulic cylinder designed working cylinder called. Of the Piston 9 is inserted in the cylinder 20 and in the working cylinder 4 themselves are return springs 5, the carriage 7th then return to its original position when the Cylinder is not pressurized. The return springs 5 are in this example in the print act on cylinder space 23.

The cylinder 4 is connected to the carriage 7 and this Carriage 7 in turn with the movable jaw 3. In the case the pressurization, the cylinder 4 moves inclusive of the carriage 7 with the mobile fixed thereto Jaws 3 on the fixed jaws too. Will the pressure withdrawn or relaxed, pull the Return springs the cylinder 4 with the carriage 7 and the movable Jaws 3 back to its original position. With small arrows indicated in the illustration according to the Fig. 1, the arrangement of the stripping elements 6, which protects against Impurities of the moving parts arranged on these are. Of course it is also possible, the invention To perform clamping device such that the cylinder. 4 is fixed and the movable piston then with the carriage. 7 and the movable jaw 3 is connected. With the Reference numeral 10 are the clamping surfaces of the fixed jaw. 2 and the movable jaw 3.

In Fig. 2 is also a sectional view of a Vice executed clamping device 1 shown. Same Reference numbers designate the same technical features therein, which have already been described in FIG. 1. On a renewed Presentation of these features is therefore omitted. With the Reference numeral 8 are bores designated by the clamping surfaces 10 of the fixed and movable clamping jaws 2,3 by lead these jaws through and through the body 11th lead in the direction of installation down. These holes 8 are intended that impurities and / or rinsing or Coolant away from the clamping surfaces 10 away become. This causes the clamping surfaces 10 always in a clean state when a new workpiece is tense. It is particularly advantageous if, for example the holes 8 with a vacuum for suction the impurities are applied.

Fig. 3 shows another variant of the invention according to the invention.

The abutment 12, which for the hydraulic or pneumatic Drive is provided, located at the suggestion of Fig. 1 at the right end of the main body 11. It is Part of the body. In the variant of Fig. 3 is the Abutment 12 part of the piston 9. In the variant of FIG. 1 the return spring 5 is in the working space 23 of the working cylinder 4 provided. The working space 23 is pressurized.

In contrast, Fig. 3 shows the arrangements of the return springs 5 in a secondary space 21, with respect to the piston on the side facing away from the working space 23. Of the Secondary space 21 is not subjected to hydraulic pressure. The return spring 5 is supported on a cover of the main body 11 from. In Fig. 1 are corresponding Installations in the working cylinder for an abutment of the Return spring 5 is provided.

The piston 9 in Fig. 3 has a pressure line 22, in which the working space 23 with appropriate working medium (compressed air, Hydraulic oil) filled and can be emptied.

Perhaps the embodiment according to FIG. 3 is somewhat more elaborate, however, it offers certain advantages during operation. The moving one Jaw 3 does not run in a pocket, as in FIG. 1, but is free. That means that in this area too no chips etc. hinder the free movement of the jaw 3. Such an arrangement is for example in the horizontal area of use Cheap.

The embodiment of FIG. 1, however, lends itself to vertical tensioning problems where the vertically standing pocket does not bother, since no chips or other falls into it or remains.

With the clamping device according to the invention it is also possible to clamp several workpieces at the same time (multiple clamping).

Claims (21)

1. Clamping device comprising at least two clamping jaws, one clamping jaw (3) being designed movably, at least one movable clamping jaw (3) being coupled with a working cylinder (4) equipped as hydraulic or pneumatic cylinder, the working cylinder (4) being arranged in the direction of mounting below the clamping surface for the work piece, characterised in that the piston (9) of the working cylinder (4) is supported stationary, and the cylinder (20) of the working cylinder (4) forms a kinematic unit with the at least one movable clamping jaw (3).
2. Clamping device according to claim 1, characterised in that the clamping device (1) has a slide guide on which a slide (7) is supported movably, and the slide (7) carries the movable clamping jaw (3).
3. Clamping device according to one of the preceding claims, characterised in that the slide (7) has a longitudinal boring which serves preferably as cylinder (20) of the working cylinder (4).
4. Clamping device according to one of the preceding claims, characterised in that the cylinder (4) designed as slide (7) is imbedded in a longitudinal recess of the basic body (11).
5. Clamping device according to one of the preceding claims, characterised in that a cylinder guide of the cylinder (20) on the piston (9) is provided separated from the slide guide.
6. Clamping device according to one of the preceding claims, characterised by parallelism, respectively quasi-parallelism, of the direction of movement of the movable clamping jaw (3) and the direction of movement of the cylinder (20) of the working cylinder (4).
7. Clamping device according to one of the preceding claims, characterised in that between stationary parts of the clamping device (1), for example the basic body (11), and the movable parts of the clamping device, for example the slide (7), stripping elements (6) are arranged as a protection against dirt.
8. Clamping device according to one of the preceding claims characterised by a clamping device (1) with a basic body (11), a stationary clamping jaw (2) arranged at the one end of the basic body (11), a slide (7) which is held at the basic body (11) in a guide, and clamping jaw (3) movable relatively to the stationary clamping jaw (2), an abutment (12) at the other end of the basic body (11) for a hydraulic or pneumatic drive of the movable clamping jaw (3), the piston (9) being supported stationary, and the cylinder (4) forming a kinematic unit with the movable clamping jaw (3).
9. Clamping device according to one of the preceding claims, characterised in that at least one restoring spring (5) is provided which returns the at least one movable clamping jaw (3) in its initial position if the cylinder (4) is not pressurised.
10. Clamping device according to one of the preceding claims, characterised in that the restoring spring (5) is located either in the cylinder space (23) which may be pressurised, or that the restoring spring (23) is located in a secondary space (21) of the cylinder opposite to the pressurising.
11. Clamping device according to one of the preceding claims, characterised in that the piston (9) receives pressure supply pipes (22).
12. Clamping device according to one of the preceding claims, characterised in that an abutment (12) is provided between the two clamping jaws (2, 3) for the hydraulic or pneumatic drive.
13. Clamping device according to one of the preceding claims, characterised in that on the clamping surfaces (10) borings (8) are provided for cleaning, respectively compressed air.
14. Clamping, respectively gripping, system with a clamping device according to one of the preceding claims 1 to 13, with a large length of stroke, in particular for a fully automatic machining line, for gripping and clamping work pieces with different shapes and sizes, and a control which adjusts the span on the clamping device basing on the differing shapes, respectively, sizes of the work pieces, and controls the clamping, respectively the gripping, of the work pieces.
15. Clamping, respectively gripping, system according to the preceding claim 14, characterised in that a vise driven by a spindle is provided for gripping and clamping the work pieces as clamping device (1).
16. Clamping, respectively gripping, system according to one of the preceding claims 14 to 15, characterised in that the control is designed in such a way that sensors determine the dimensions of the work pieces, or the work piece has a data carrier for or with the dimensions, the control reads the sensors or the data carrier, and the control transmits suitable signals to the drive of the clamping device (1) in order to adjust the clamping device (1) to the determined size of the work piece.
17. Clamping, respectively gripping, system according to one of the preceding claims 14 to 16, characterised in that the clamping of the work piece, in particular along the complete stroke, is carried out by clamping, respectively pressure, power which can be adjusted, respectively selected, in advance.
18. Clamping, respectively gripping, system according to one of the preceding claims 14 to 17, characterised in that an installation for adjusting and/or monitoring the clamping power for clamping the work piece as well as the position, respectively the shifting path of the jaws, is provided.
19. Clamping, respectively gripping, system according to one of the preceding claims 14 to 18, characterised in that the control has a storage where the values for span, clamping power as well as the different shapes and sizes of the work pieces can be deposited and stored.
20. Method for machining work pieces with different clamping sizes, the work pieces being gripped and, if necessary clamped, by a clamping, respectively gripping, system according to one of the preceding claims 14 to 19, and the method adjusts accordingly the gripping width, respectively the span, on the clamping, respectively gripping, system basing on the different sizes which have to be gripped, respectively clamped.
21. Method according to claim 20, characterised in that clamping of the work piece is only possible when it is confirmed that the gripping width, respectively span, corresponds with the respective set value with reference to the clamping size of the work piece, if necessary within suitable tolerances.

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