DE4000948A1 - Safety system for e.g. automatic machines - have one member moved from position set by second member by force exceeding set level and moved within distance limited by third member - Google Patents

Abstract

A safety system for machinery etc, has at least one member which is moved by another member when a force exceeds an adjustable given value; it has at least one static member to set the starting position of the moving member and at least one force-transmitting member to act on the two other members; the system also has means of limiting movement to a set amt. In an example a cylinder (1) has a partition (2) dividing it into two parts, each with a rod (5,6) fitted with flange (7,8) and pressure spring (9.10). One spring (9) is fixed to the partition (2); the other (10) is fixed to the other end (4) of the cylinder. The springs thus set the initial positions of the rods (5,6). If a force above a set level acts on the LHS end of the rod (5) this (5) moves and compresses the spring (9). A tension applied to the rod (6) moves the cylinder (1) to the left. The effect is that a force above a particular level moves the left hand or right hand half of the system and hence changes the distance between the ends of the two rods (5) and (6). ADVANTAGE - the system detects overloads in a reliable manner and releases them until the system is not endangered and then stops the whole layout.

Description

The invention relates to a full security system for use on a machine tool or in a comprise several machine tools and auxiliary devices the production plant in which workpieces are cutting processed, transported and checked. In particular the invention is directed to a full security system, which indicates the occurrence of a preselected value exceeding force and the machine tool or a processing system in a safe area drives back to prevent that on individual Parts of the machine tool or processing system excessive forces damage the affected Parts or the machine tool or processing system overall lead.

The invention further relates to one in such Fully safety system usable actuator, on one with a memory and a full security system Machine tool equipped according to the invention equip one with such a full security system machine table, one with such full security system interacting tool holder and on a Device for measuring a thrust on a shaft.

The automation of Manufacturing equipment pursues the purpose of such equipment in twenty-four hour operation without operating personnel to let work. There are already numerous tools machines or processing equipment, of which claims is that they have no operators in twenty-four could work hourly. In fact, there is no machine tool or processing system yet is able to do that. For machine tools, etc. the before standing type it is possible to use Tools and the movements of workpieces in one To program NC (Numeric Control) computers in the  practical execution of numerical in this way computer-controlled operations, however, are common Errors and mistakes in programming, not to be foreseeable failures and damage to tools or due to unforeseeable changes in condition of unexpected changes around the workplace.

To work on such machine tools, etc. as a result of excessive Load on a tool or workpiece To prevent disturbances and difficulties, it is necessary the corresponding sources of error or unpredictable Detect events automatically and in good time and the machine tool or the like for safety reasons to shut down.

Safety devices designed for this purpose must not only be provided on individual machine tools but also on auxiliary devices such as robots as well Transfer and transport devices, d. H. so on all components of a machine tool or machining investment.

There are already suggestions for e.g. B. in processing plants usable electrical devices for the Detection of faults, e.g. B. overloads, by means of Current or voltage changes in responsive sensors, or other facilities that use a tool at Über exceeding a predetermined load, e.g. B. one predetermined torque, disengage and an electric Signal to immediately stop a machine tool produce. Another trained for such purposes Safety device acts on a tool Workpiece or a machine table exercised corresponding Force on a deliberately poorly trained one a so-called mechanical securing part so this with excessive reinforcement on it Exerted force breaks and thereby breaks others Prevents parts of the machine tool or the like.

For one with an electrically working safety equipped of the type described above  Machine tool, however, may experience certain malfunctions cannot be recognized, for example due to overload caused breakage of a fine and therefore weak work stuff, because in this case the detection signal is very weak is. The processing is then ignorant of the Tool breakage continued. If it is broken tool z. B. a drill or a forehead milling cutter, the further rotation of the work occurs evidence of a strong warming of himself and the Workpiece. Depending on the type of in such a case The cutting oil used results in an acute fire danger to the machine tool or the entire system. There are already numerous such dangers in Japan alone situations and accidents occurred.

Mechanical fuses used in machine tools are capable of transferring excessive forces to the important parts and functional elements of the machine itself prevent effectively. After a break of one mechanical fuse must be removed from the tool machine removed and replaced with a new one. At Such a mechanical fuse can, however also a person capable of absorbing relatively strong forces trade a larger part, the replacement of which is difficult after a break is sam and expensive.

Given the identified shortcomings, which has been around for some time Time or just recently for such manufacturing or Machining systems available security systems purposes the invention the creation of a novel fully secure system, which is able from any Founding essential components of a manufacturing or Machining system safe overloads recognize a relief of the affected components to bring about the plant in safe operation area, and then the entire plant to shut down.

Occurs when using the fully secure according to the invention unit on a machine tool, for example  Disturbance, e.g. B. such that a security system acting Krfat a set value over increases, then a workpiece can, for example, by several Millimeters in the direction of the force acting on it dodge. Simultaneously with the beginning of this evasion movement is a signal to the controller that indicates this the machine tool, due to which the tool machine is stopped immediately. Such a full security system is of course not only for suitable for fully automated production systems, but also for other susceptible to failure and therefore plants requiring security, e.g. B. for systems in which a force to monitor and when certain occur Conditions to below a preselected value is decrease for plants in which the form of a Component of the same monitored and a deformation of this To be displayed partially, or for other plants, in those not envisaged temperature changes and the presence of dangers indicated by sound signals can be.

Security systems for such and other systems can all on the full security system according to the invention build up.

For the operation of the full security system according to the invention two functions are necessary. One function exists in one of one hereinafter referred to as a force element neten part with a force, hereinafter as Movement element designated part to move. Exceeds the force exerted by the force element is set Value, then the moving element moves in the direction the force acting on it. The second function exists in the occurrence of a fault in which the Force element exerted on the movement element set value to generate a signal to so that the system returns to the safe operating area to drive.

Between the generation of a malfunction  indicating signal and the final standstill z. B. a machine tool, inevitably occurs a certain Delay on. That's why it's on a machine tool Full security system to be used according to the invention preferably designed so that a workpiece A set value exceeded on it exerted force moved a little bit and that for generation of the machine control Signals a responsive to this movement of the workpiece Element is provided.

The delay mentioned above arises in all of them Machines made up of several factors. A first delay results between the exceeding of the set Worth a force acting on any part and that Responding to this overshoot. A second delay arises in an amplifier between the generation of the Signal by a sensor and receiving the signal from the control. When using an analog-digital conversion there is a third delay in the system. A fourth delay arises between reception of the Signal from the controller and the detection of the signal by the control. The delays mentioned above thus arise solely in the generation, transmission and Processing of the signal and the data transmitted with it Information.

There is another delay between that Time at which the controller detects the existence of a Detects disorder and the time at which breastfeeding set the machine tool is initiated. This too There is a delay in generation and transmission of the corresponding signal. Another critical delay tion arises between the time when the breastfeeding set the machine tool is initiated, and the full constant machine standstill. During this period the moving parts run due to their inertia continue with decreasing speed until finally come to a standstill.  

The two delay factors mentioned above are inevitably unavoidable, since the first comes from the after resulting electronic switching operations and the second is based on the fact that the moving parts have a given mass of the machine.

Unless the machine tool is equipped with any equipment is equipped, which are able to due to the inertia of the moving parts open delay between the occurrence of a fault and the complete stoppage of the moving parts moving parts can increase or compensate or the machine tool overall significant damage suffer. To overcome the difficulties discussed above eliminate and a fully automated processing processing or manufacturing operation without operating personnel allow, a machine tool is preferably so to train that a force acted upon by a force supply element when reaching or exceeding one selected value of the force acting on it evasive movement until the machine tool comes to a standstill, whereupon the parts of the machine then after the disorder disappears back to its original positions.

The through the full security system according to the invention considerations have a positive and a negative direction, as explained below.

When machining a workpiece, for example by means of an end mill 331 shown in FIG. 60 of the drawing, both the workpiece and the tool are subject to forces from all directions, which are usually represented by the X, Y and Z axes and each have a positive and a negative scalar or vector. When the metal workpiece 330 is processed by means of the milling tool 331, it moves in the direction of the positive and negative scalars of the X, Y and / or Z axes. With each movement of the milling tool 331 , the direction of the forces acting on the workpiece 330 and the tool itself changes accordingly. When forming a threaded bore in a workpiece 332 by means of a corresponding drilling tool 333 , as shown in Fig. 61, only a thrust and a torque are to be taken into account. In addition, excessively strong forces can be exerted on the workpiece when the tool used to produce the threaded bore is pulled out of the workpiece. As explained above, the forces occurring during machining can be divided into positive and negative scalars or direction vectors along the X , Y and Z axes. Accordingly, a full security system must be designed to respond to opposing forces along the X , Y and Z axes.

A safety system which responds only to a positive or negative force in the direction of only one of the axes X , Y or Z can be represented without difficulty. In such a simple safety system, a movement element is supported, for example, by a spring on a part of a static system and, when a predetermined value of a force acting on it from outside comes into contact with a stop, via which a device for executing an evasive movement can be actuated . However, the representation of a security system that responds to both positive and negative forces in the direction of the X , Y and Z axes offers considerable difficulties. For example, in the device shown in Fig. 62, a phenomenon described below in an individual, referred to as "parallelism of forces" occurs, so that it is not possible with such a device to create a fully functional safety system which the has the high precision necessary for a modern machine tool.

In Fig. 1 to 4 of the drawing, the characteristics essential for a reliable full security system are Darge presents. In these figures, the abscissa corresponds to a force ( f ) acting on a part of a machine tool and the ordinate corresponds to the movements ( X ) of the part in question. As long as the strength of the force ( f ) lies in the area I, hereinafter referred to as neutral area, between the points - f ₀ and + f ₀ on the abscissa, no movement X takes place. However, if the force shifts from area I in the plus or minus direction to area III or II, movements X proportional to this shift occur. The proportionality of these movements need not be linear, but can also follow the shape of any curve.

Although it is permissible for the movement curve to run parallel to the ordinate as shown in FIG. 2, in practice the course of the movement shown in FIG. 1 deserves preference, since in this case the construction of the system is simplified.

If the movement curve shown in Fig. 1 has the form of hysteresis curves shown in Fig. 3, there is an increased effectiveness in the operation of the security system. The characteristics of the security system shown in FIGS. 2, 3 and 4 can be simplified in the form shown in FIG. 1 in order to obtain a safely operating security system.

Machine tools need a great deal of stability point and may be compared to those in normal operation do not give in to occurring forces, especially none Allow evasive movements before moving on one forces exerted on a predetermined value rise, so that one for such a machine tool security system provided in areas I, II and III must have the characteristics shown.

In known security systems of the type in question, the neutral area I and essential sections from the characteristic curves shown in FIGS . 1 to 4 are missing. FIG. 62, 303 in which shows an apparatus used in such a known safety system comprising a housing 301 and two spring chambers formed therein 302, respectively, a compression spring 304 or 305 is housed. The spring chambers 302 , 303 are penetrated by a shaft 306 which carries a flange 307 in the middle. The two compression springs 304 , 305 are each supported by a stop 308 and 309 on the flange 307 and on a partition 310 separating the two spring chambers 302 and 303 from each other.

At first glance it appears here that the relationship between a force ( f ) exerted on the shaft 306 of the known device and the movement X corresponds to the ideal case shown in FIG. 1. In reality, however, this is not the case since it is practically impossible to design the partition wall 310 , against which the stops 308 and 309 are in contact, and the flange 307 with exactly the same thickness. If the thickness T of the partition wall is greater than the thickness t of the flange, the relationship between the force f and the movement x shown in FIG. 63 results. The neutral region I x here runs in the direction of the movement, that is to say the ordinate, and not along the abscissa, so that a certain play is present in the device. Fig. 65 shows the situation in which T is smaller than t . In this case there is no neutral zone at all. As long as the device is acted upon by a force within the differential range between T and t , both compression springs are thus effective at the same time. Fig. 64 shows the ideal state in which T is t and the device has the characteristic shown in Fig. 1.

The shortcomings of the Vorrich device described above result from the fact that a force exerted on it is divided into two parallel forces. If, for example, the shaft 306 is shifted to the left in FIG. 62, a part of the force exerted on it with A is transmitted to the housing via the stop 308 and the compression spring 304 , while another part of the force f denoted by B is transmitted the other stop 309 and the other compression spring 305 acts on the housing.

In this device, the force f is thus divided into the two forces A and B when it is transmitted. This results from the fact that two modules, each consisting of a compression spring and a stop, are arranged on one and the same shaft, so that a force exerted on the shaft is effective in both modules. This phenomenon was referred to above as "parallelism of forces". This parallelism of the forces leads to an undesirable characteristic in the transmission of the force f due to the difference between the strength T and the strength t . To eliminate this disadvantageous property, the device would have to be designed in such a way that the forces after their division do not flow parallel next to one another, but in series one after the other through the device, which could be achieved in that the two modules, each consisting of a stop and a spring, are connected in series arranged in a row.

Fig. 66 shows a spindle drive for positioning of parts of a machine tool. If the spindle 311 of the spindle drive at both ends of corresponding support devices, for. B. hydraulic dampers or springs 313 and 314 is supported, the spindle drive apparently has the characteristic shown in Fig. 1 of a safety system. A rotating part 312 can be set in motion by the rotation of the spindle 311 . The the Move Liche part 312 supporting spindle 311 is supported at two points so that 312 forces exerted thereon will carry as shown in FIG. Vorrich shown 62 tung parallel to each other on a static system on the movable part, from which the in Fig . 63 or 65 Darge introduced, is obtained for a full security system adverse characteristics.

Regardless of the fact that the resulting characteristics are more or less identical to those shown in Fig. 63 or 65, the presence of a neutral area, even if only a few thousandths of a millimeter, can in some cases be similar to that in Fig. 64 Lead characteristic.

Fig. 67 shows a hydraulic valve with a force-neutral region comprising reset means 315 with a spool 316 and a spring 317th The reset device 315 connected to a hydraulic slide 318 in the manner shown in FIG. 68 is always in the neutral position. The hydraulic slide 318 cannot be actuated as long as a force exerted on a lever 319 serving to actuate it does not exceed a predetermined value, so that the slide 318 thus has a corresponding neutral range. However, it would not make sense to use such a device in a safety system for a machine tool, in which certain parts have to be positioned with high accuracy.

It is therefore an object of the invention to provide a full safety system which has the corresponding force-movement characteristics shown in FIG. 1 and in which the transmission of external forces takes place in series.

Another object of the invention is to create a usable as part of such a security system Actuator, which under the influence of it external force applied from outside occurs.

Another object of the invention is to create an as Part of such a security system usable memory with an elastic body for storing over transmitted a hydraulic or pneumatic system Forces when using such a hydraulic or pneumatic system for actuating a movement elements of an actuator.

The invention also aims to provide a tool machine with a machine table and a tool holder, which are each coupled with a full security system are.

Furthermore, the invention aims to create a front Direction for measuring and monitoring the axial thrust  a wave for determining a set value the force at which the full security system in Effect occurs.

Exemplary embodiments of the invention are described below the drawing explained. Show it:

Figs. 1 to 4 are graphs of power movement characteristics of the full security system according to the invention,

Fig. 5 is a schematic view of an element of a security system in a first embodiment of the invention,

Fig. 6 is a representation of the effect of the first embodiment,

Fig. 7 is a Fig. 5 corresponding view of a second embodiment,

Fig. 8 is a Fig. 7 corresponding view of a third embodiment,

Fig. 9 is a representation of the effect of the third embodiment,

Fig. 10 is a schematic representation of a fourth embodiment,

Fig. 11 is a schematic representation of a fifth embodiment,

Fig. 12 is a Fig. 11 corresponding view of a sixth embodiment,

Fig. 13 or a corresponding view of a seventh embodiment

Another embodiment of an energy accumulator Fig. 14 in Fig. 13 shown

Fig. 15 is a schematic representation of the operation of the seventh embodiment,

Fig. 16 is a schematic representation of an energy accumulator used in the seventh embodiment,

Fig. 17 is a schematic representation of an energy accumulator, in another embodiment,

Fig. 18 is a schematic view of an eighth embodiment of the invention,

Fig. 19 is a diagram of the force-movement characteristic of the eighth embodiment,

Fig. 20 is a schematic representation of a ninth embodiment of the invention,

Fig. 21 to 23 schematic illustrations of execution forms with magnetic Kraftübertragungseinrich obligations,

Fig. 24 is a schematic representation of the machine table of a machine tool and an associated therewith security system,

Fig. 25 generating machine is a block diagram of a numerically controlled drive and an associated security systems,

Fig. 26 is a schematic representation of a machine tool with a safety system according to the invention,

Figure 27 to 30 schematic illustrations of an actuator 26 used elements. In the embodiment according to FIG.

Fig. To 33 schematic representations of means for generating a triggering signal for the safety-system 31,

Fig. 34 is a schematic representation of a hydraulic actuator according to the invention,

Fig. 35 is a schematic representation of a hydraulic force storage means according to the invention,

Figure 36 and 37 are graphs showing the. Force-motion characteristic and the operation characteristic of a model of the safety system according to the invention,

Fig. 38 is a graph of dynamic force and motion of an end mill,

Fig. 39 is a schematic representation of the use of a safety system for low load,

Fig. 40 to 48 schematic illustrations of execution of a machine table form with a safety system,

Fig. 49 and 50, schematic representations of parts of the safety system for a machine table in other embodiments,

Fig. 51 is a schematic representation of a tool holder equipped with a safety system,

Fig. 52 is a sectional view of a tung Betätigungseinrich used in an embodiment of an inventive device for measuring a shaft thrust,

Fig. 53 is a sectional view of a shaft bearing housing for use in another embodiment of a device for measuring the shaft thrust,

Fig. 54 is a schematic representation of a Wellenschub- measuring ring,

Fig. An enlarged view of in FIG. 54 as "a" designated cutout 55,

Fig. 56 is a schematic representation of one of the exporting approximate shape of FIG. 53 corresponding to the spring system,

57 is a diagram of the force-movement characteristic of the system. Shown in Fig. 56

Fig. 58 is a sectional view of an in another exporting an apparatus for measuring the approximate shape shafts usable thrust sleeve,

Fig. 59 is an enlarged view of the, in Fig. 58 by "b" detail denoted

Fig. 60 and 61 schematic oblique views illustrating the in machining a workpiece on passing forces and their directions,

Fig. 62 and 66 schematic illustrations of known devices,

Fig. 63 to 65 are diagrams of the power movement characteristics of known devices, and

Fig. 67 and 68 schematic illustrations of a further known apparatus.

Fig. 5 to 12 show various embodiments of parts of a security system according to the invention, in which for the transmission of forces to a motion element a resilient member, in particular a spring is seen before. In particular, these figures show various embodiments of an actuating element which can be moved under the action of a force exerted thereon by a force element.

In one embodiment shown in FIGS. 5 and 6, a spring is used as the elastic element. In Fig. 5 you can see in a schematic representation a cylinder 1 , a in the longitudinal center of the cylinder 1 arranged partition 2 , the cylinder 1 final end walls 3 and 4 , a pair of connecting rods 5 and 6 , each having a flange at their inner ends 7 and 8 wear, and arranged in the cylinder 1 compression springs 9 and 10th The spring 9 is supported at one end on the partition 2 and at the other on the flange 7 . The spring 10 , however, is supported with one end on the flange 8 and the other on the end wall 4 . The cylinder 1 and the compression springs 9 and 10 determine the force which can be absorbed by the actuating element, which is denoted overall by 47 , and define the starting positions of the connecting rods 5 and 6 .

The operation of the actuating element 47 is shown in FIG. 6: If a force element (not shown) exerts a force f exceeding a predetermined value f ₀ on the left end of the connecting rod 5 , then this moves, as in the upper part of FIG. 6 shown, with compression of the compression spring 9 in the cylinder 1 to the right. This movement of the connecting rod 5 shown in the middle part of FIG. 6 by the amount X shortens the distance between the ends of the connecting rods 5 and 6 by the same amount X. If, on the other hand, a negative force -f exceeding a predetermined value F ₀ , that is to say a tensile force is exerted on the connecting rod 6 , as shown in the lower part of FIG. 6, the cylinder 1 moves to the left, the compression spring 9 not changing its state while the other compression spring 10 is compressed. The distance between the ends of the connecting rods 5 and 6 increases by the amount X corresponding to the movement of the cylinder.

As can be seen in FIGS. 5 and 6, the flange 7 can be brought into and out of contact with the end wall 3 and is therefore effective together with the latter as the first stop member. In a corresponding manner, the flange 8 and the partition 2 act together to form a second stop member. The compression spring 9 , the partition 2 and the first stop member together form an active member A , while the compression spring 10 , the end wall 4 and the second stop member together form an active member B. In relation to a force exerted on the connecting rod 5 , the two active members A and B are arranged in series one behind the other.

Accordingly, the action of a force exceeding the predetermined value between the connecting rods 5 and 6 leads to a movement of the active member A or the active member B. The actuating element 47 thus enables an evasive movement when the force acting in one direction or the other on the connecting rods 5 and 6 exceeds the predetermined value, so that the characteristic shown in FIG. 1 results.

Whenever the distance between the ends of the connecting rods 5 and 6 changes , a conventional microswitch or breaker is immediately actuated to report the movement in question. The output signal of the switch or interrupter can be used to shut down a device which exerts the force. In the arrangement shown in FIG. 5, the prestressing of the compression springs 9 and 10 can be varied by displacing the end walls 3 and 4 in the direction of the longitudinal axis of the cylinder 1 and thus the respective value of the force f ₀ + or f ₀ - can be selected which the evasive movement begins. The values for f ₀ + and f ₀ - can also be set to different sizes, so that neutral areas of different widths are obtained on the plus side and the minus side.

In the second embodiment of the invention shown in FIG. 7, tension springs 11 and 12 are provided as force-transmitting elements. The tension spring 11 is anchored to the partition 2 of the cylinder 1 and to the flange 7 of the connecting rod 5 , so that the flange 7 is loaded in contact with the outside of the end wall 3 of the cylinder 1 . The tension spring 12 is anchored at its ends to the flange 8 of the connecting rod 6 and to the other end wall 4 of the cylinder 1 , so that the flange 8 is loaded in contact with an annular wall 201 in the cylinder 1 .

Practices a force element (not shown), e.g. B. the machine table of a machine tool, a predetermined value - f _n exceeding, directed to the left in Fig. 7 pulling force on the end of the connecting rod 5 , then the state of the tension spring 12 remains unchanged while the other tension spring 11 stretches, so that the distance between the ends of the connecting rods 5 and 6 increases. If a corresponding force f acts on the connecting rod 5 in the opposite direction, the state of the tension spring 11 or the position of the connecting rod 5 relative to the cylinder 1 remains unchanged, while the connecting rod 6 moves into the cylinder 1 while the tension spring 12 is stretched , so that the distance between the ends of the connecting rods 5 and 6 is shortened.

In a similar manner as in the first embodiment, the force exerted by the force element acts also in series to an out of the tension spring 11, the partition wall 2 and that of the end wall 3 of the cylinder 1 and the flange 7 of the connecting rod 5 formed first stop member formed effector A and Onff of the tension spring 12, the other end wall 4 and from the ring wall 201 within the cylinder 1 and the flange 8 of the other connecting rod 6 gebil Deten second stop member existing effector B, so that the characteristic shown as a diagram in Fig. 1 obtainable is. A change in the predetermined values for f ₀ + and f ₀ - can be achieved by displacing the end walls 3 and / or 4 along the axis of the cylinder 1 .

The third embodiment shown in FIGS . 8 and 9 has a compression spring and a tension spring as force-transmitting members. As can be seen in Fig. 8, the actuating element for a security system in this embodiment of the invention has two cylinders 13 , 14 with end walls 15 , 16 and 17 , 18 , a tension spring 19 arranged in the cylinder 13 , a pressure accommodated in the cylinder 14 spring 20 and a connecting rod 21 with two flanges 22 and 23 . The power transmission takes place here via the connecting rod 21 with its flanges 22 and 23 and the springs 19 and 20 .

As can be seen in the upper part of Fig. 9, the flange 22 of the connecting rod 21 in contact with the end wall 16 of the cylinder 13 and the flange 23 in contact with the end wall 17 of the other cylinder 14 is loaded. When a thrust force f directed to the right, exceeding a predetermined value + f ₀ , is exerted on the cylinder 13 , as shown in the middle part of FIG. 9, the cylinder 13 moves to the right with compression of the compression spring 20 , so that the distance between the ends increases of the two cylinders 13 and 14 shortened by a corresponding amount X. If, on the other hand, a tensile force f exceeds a predetermined value - f ₀ , acts on the cylinder 13 , then this moves, as shown in the lower part of FIG. 9, with the extension of the tension spring 19 to the left, so that the distance between the ends of the Cylinder 13 and 14 enlarged by the amount X. The characteristic shown in FIG. 1 can thus also be achieved in this embodiment. Changes in the predetermined values + f ₀ and - f ₀ can be achieved by displacing the end walls 15 and 18 in the axial direction of the cylinders 13 and 14, respectively.

In the fourth and fifth embodiments of the invention shown in FIGS. 10 and 11, the arrangement of the cylinders and the flanges of the connecting rod is reversed with respect to the arrangement shown in FIGS. 5 and 7, respectively.

As can be seen in FIGS. 10 and 11, the flanges 33 and 34 bear against the end walls 26 and 28, respectively. If a thrust force is exerted on the cylinder 24 to the right in the drawing and exceeds a predetermined value + f ₀ , the compression spring 31 is compressed so that the distance between the cylinders 24 and 25 is shortened. If, in the fifth embodiment, a left-hand tensile force f exceeding a predetermined value - f _{0 is} exerted on the cylinder 24 , the latter moves to the left while the tension spring 36 is being stretched, the flange 34 of the connecting rod 32 being removed from the end wall 28 of the cylinder 25 is lifted off. The fourth and fifth embodiments are designed to be complementary to one another and can both have the characteristic shown in FIG. 1. Changes in the predetermined values for + f ₀ and - f ₀ can be achieved by axially displacing the respective end walls.

Fig. 12 shows a sixth embodiment in which two compression springs 43 and 44 are arranged concentrically one inside the other. The end wall 41 of an inner cylinder 40 is loaded against the end wall 39 of an outer cylinder 37 , and a flange 46 of a connecting rod 45 is loaded against the other end wall 42 of the inner cylinder 40 . Is the in the drawing to the right pointing end of the connecting rod 45 a a predetermined value - exerted f ₀ on rising rightward pulling force f, then the compression spring 44 concentrically inserted into the inner cylinder 44 is compressed, while the distance between which free End of the connecting rod 45 and the rear end wall 38 of the outer cylinder 37 enlarged. If, on the other hand, a shear force f , which exceeds a predetermined value + f ₀ , acts on the free end of the connecting rod 45 , the connecting rod 45 moves under compression of a compression spring 43 inserted into the outer cylinder 37 between the end wall 41 of the inner cylinder designed as a flange 40 and the rear end wall 38 of the outer cylinder 37 to the left, so that the distance between the end of the connecting rod 45 and the end wall 38 is shortened accordingly. The characteristic shown in FIG. 1 can also be achieved in this embodiment. The predetermined values + f ₀ and - f ₀ can in turn be changed by setting the end walls 42 and 39 .

The above descriptions of the embodiments two to six, as well as the description of the first embodiment, each relate only to the design of the actuating element 47 , it being noted here that, in addition to the actuating element 47 described, devices responsive to the movements of the moving element are also part of a full security system according to the invention for generating corresponding signals and devices responsive to such signals for stopping the movement of a force-exerting element. In Fig. 13 to 16, an operating with a hydraulic system seventh embodiment is shown in which the transmission takes place of forces by the actuation member 47 as well as in an energy storage 48 contained oil, which also serves to at least one movement element, z. B. a piston to continuously apply a predetermined force. Fig. 13 shows the basic structure and the operational principle of the seventh embodiment in which the security system, an actuator 47, and a power storage 48 comprising. The actuating element 47 has a cylinder 49 divided by a partition 50 , in which two pistons 53 and 54, each connected to a piston rod 51 , 52 , are displaceable. A line 55 connects the cylinder 49 with the energy accumulator 48 representing a hydraulic power source. This has a cylinder 56 , a piston rod 57 with a piston 58 at one end and a flange 59 at the other end, and a compression spring 60 arranged between the flange 59 and a fixed wall 61 . The cylinders 49 and 56 and the line 55 are completely filled with oil 62 .

Instead of the springs used in the above-described embodiment for one to six, the seventh embodiment works with a single compression spring 60 assigned to the energy accumulator 48 , the force of which is transmitted to the two pistons 53 and 54 by the oil. On the other hand, forces exerted via the piston rods 51 and 52 are stored in the compression spring 60 of the energy accumulator 48 . The starting positions of the pistons 53 , 54 are determined by the pressure conditions of the oil 62 in the energy accumulator 48 and in the cylinder 49 . It is also possible to use another energy accumulator of the type shown in FIG. 14 in the form of a closed container which is partially filled with oil 62 , a gas cushion 63 taking on the role of the compression spring 60 . Furthermore, a pneumatic safety system is also possible, in which the cylinders 49 and 56 and the line 55 with gas, for. B. air are filled.

To explain the mode of operation of the embodiment shown in FIG. 13, only the actuating member 47 is shown in FIG. 15 with the energy accumulator 48 omitted.

In the initial state of the actuating element shown in the upper part of FIG. 15, the pistons 53 , 54 connected to the piston rods 51 , 52 are in contact with the left end wall or with the partition 50 of the cylinder 491 due to the hydraulic pressure exerted by the energy accumulator 48 . Held 492 . If a force element (not shown) exerts a pushing force f on the piston rod 51 that exceeds a predetermined value + f ₀ , then this moves to the right by the amount X , the piston 53 displacing oil from the cylinder 491 and the force accumulator 48 feeds so that its compression spring 60 is compressed. This state is shown in the middle part of FIG. 15.

If, on the other hand, an opposite tensile force, exceeding a predetermined value - f ₀ , is exerted on the piston rod 51 , then the movement of the piston 54 to the right leads to an increase in the hydraulic pressure in the cylinder 492 and thus to the compression of the compression spring 60 . The distance between the ends of the piston rods 51 and 52 increases by the amount X of the movement of the piston 54 .

The characteristic shown in FIG. 1 can also be achieved in this embodiment, in which switches (not shown) respond to corresponding movements of the piston rods 51 and 52 in order to control the movement of the force element exerting the respective force, e.g. B. a machine part to bring to a standstill. In a hydraulically or pneumatically operating a security system of the type described above, the possible results ness, 47 spatially separated by a force store 48 to locate the responsive to the application of a force actuator. This in turn gives you the option of adjusting the hydraulic or pneumatic pressure by external intervention and thereby determining the values for + f ₀ and - f ₀ . In the embodiment shown in FIG. 13, the values for + f ₀ and - f _{0 can} thus be set by changing the distance between the pressure accumulator 48 and the fixed wall 61 .

If, in the embodiment according to FIG. 13, a common pressure source is used for the two pistons 53 and 54 and the pistons and the cylinders assigned to them have the same diameter, the absolute values for + f ₀ and - f ₀ are not the same , so that the neutral areas on the plus and minus sides of the force f are different in width. By using different pressure sources for the two pistons 53 , 54 and / or by choosing different diameters for the pistons 53 , 54 and the cylinders assigned to them, it is possible to obtain the same values for + f ₀ and - f ₀ . In this case, too, these values can also be set differently. This mode of operation can be achieved both in a safety system which works with hydraulic pressure and in a safety system which works with pneumatic pressure.

Fig. 16 shows details of a working hydraulic pressure actuating member 47. The wall of the actuating element 47 is penetrated here by holes 64 for the connection of the lines 55 . In the case of actuating elements 47 operating with hydraulic or pneumatic pressure, the sealing between the pistons 53 , 54 and the cylinders 49 associated with them often presents considerable difficulties. In such cases, a bellows 65 can also be used instead of the pistons and cylinders, as shown in FIG. 17.

Fig. 18 shows an eighth embodiment of a safety system in which it works with hydraulic pressure and has a pressure relief valve. The eighth embodiment of the safety system includes an actuating element 47 working with hydraulic pressure and a force accumulator 48 with a spring 60 . In addition to the spring 60 to the energy accumulator 48, a control unit 67 , a hydraulic motor 68 and a spindle drive 69th When the spindle drive 69 is driven by the hydraulic motor 68 , a movable element thereof, on which the compression spring 60 is anchored at one end, moves in the axial direction of the compression spring 60 in order to change the force or energy stored therein. In this way it is possible to set the values + f ₀ and - f _{0 of} the forces acting on the pistons 53 and 54 .

When using an adjustable pressure relief valve 76 in connection with the energy accumulator 48 , the relevant end of the compression spring 60 can also be arranged in a fixed manner. In this case, an energy accumulator 48 of the type shown in FIG. 14, working with a gas cushion 63 , can also be used.

As can be seen in FIG. 18, a check valve 701 is inserted in line 55 . Between the check valve 701 and the cylinder 56 of the energy accumulator 48 , the adjustable pressure relief valve 76 is arranged and connected to a pressure medium container 77 . The pressure relief valve 76 is adjustable via the control unit 67 . The above-mentioned elements together form a main pressure circuit on which a shut-off valve 71 , a pump 73 and a pressure medium tank 74 comprising construction group and a shut-off valve 72 and a pressure medium tank 75 comprising further assembly are ruled out.

In this embodiment of the safety system, the check valve 701 allows the flow of the pressure medium from the actuating element 47 to the power feed valve 48 or to the adjustable pressure relief valve 75 . An adjustable throttle valve 702 arranged parallel to the check valve 701 allows the throttled return flow of the pressure medium to the cylinder 49 for the return of the piston 53 or 54 to the starting position after a response of the safety system.

The pump 73 is operable to supply the main pressure circuit with a pressure medium, and the shut-off valve 72 serves to discharge the pressure medium from the main pressure circuit.

By using the effective in a known manner to keep the hydraulic pressure in the pressure circuit effective pressure relief valve 76 in conjunction with the energy accumulator 48 , it is possible to prevent a further increase in the force exerted by the force element f after the response of the safety system, so that the in Fig. 19 Darge set relationship between the force f and the movement of X is obtained. This relationship presents itself as a combination of the characteristics illustrated in FIGS. 1 and 2. This ensures that the force acting on the system never exceeds a predetermined value + f ₀ or - f ₀ , so that the different parts of a tool machine and workpieces machined by it and the like are safely protected from damage.

In the described embodiment, it would in principle be possible to omit the energy accumulator 48 and use the adjustable pressure relief valve 76 alone, but in this case the pressure circuit would not contain any hydraulic pressure source, and the forces acting on the actuating element 47 and emanating from it would have to be avoided springs included in the system are included. In addition, a precise movement control of the actuating element 47 would hardly be achievable due to pressure medium leakage losses.

In the ninth embodiment shown in FIG. 20, two cylinders 78 , 79 are arranged concentrically around a piston 80 . The ninth embodiment thus corresponds to the sixth embodiment, the springs used there being replaced by hydraulic pressure elements, so that the characteristic shown in FIG. 1 can be achieved as in the embodiments described above. The actuating element 47 shown in FIG. 20 can of course also be used in the safety system shown in FIG. 18.

In the safety system described above and the associated actuating element 47 , magnetic forces generated by permanent magnets or electromagnets can be used to control the response behavior. In particular, the magnetic forces generated by electromagnets can be controlled by regulating the voltage or the current for the electromagnets by means of an external control circuit, in order in this way to optionally determine the force to which the safety system should respond.

In Figs. 21 to 23 are connected to such processing tends electromagnet actuating elements for a security system provides Darge. The embodiment shown in Fig. 21 has electromagnets 151 , 152 and compression springs 153 , 154 , the embodiment shown in Fig. 22 works with electromagnets 151 , 152 and a hydraulic pressure circuit for power transmission, and the embodiment of Fig. 23 is alone provided with electromagnets 151 , 152 . In the embodiment according to FIG. 22, the cylinders 49 filled with oil 62 are fluidly connected to an energy accumulator 48 as in FIG. 13. In all three embodiments according to FIGS. 21 to 23, the pistons 51 , 52 are made of a material of high permeability, so that they are constantly attracted by the electromagnets 151 and 152 , respectively.

21 is applied to the piston 51 of the embodiment of FIG. 21 a compressive force exceeding a predetermined value + f ₀ , the piston 51 moves overcoming the attractive force of the electromagnet 151 and compression of the compression spring 153 to the right, so that the distance between the Ends of the two pistons 51 and 52 shortened accordingly. On the other hand, a tensile force f exceeding a predetermined value - f _{0 is} exerted on the pistons 51 , 52 , e.g. B. shown in Fig. 6, then the actuation characteristic shown in Fig. 4 results, since the attractive force of the electromagnet is inversely proportional to the square of the distance between the two parts.

Fig. 24 shows the use of a safety system of the type described above on a horizontally movable machine table 81 having a machine tool. The table 81 is driven by a motor 82 and a spindle drive 83 with the interposition of a hydraulic actuating element 47 in this case. Of course, this can also act on the spindle of the spindle drive 83 driven by the motor 82 .

In the arrangement shown in Fig. 24, the table is e.g. B. stored on a linear guide arrangement, so that it is movable bar in one direction to the left and right. The transmission of the drive of the motor 82 to the table 81 takes place via the spindle drive 83 and the actuating element 47 , which here has a cylinder 49 and two pistons 51 , 52 which can be displaced therein. The two oil-filled chambers of the cylinder 49 are connected via a line 55 with a force accumulator 48 . As long as a certain value not exceeding force f is exerted in a horizontal direction on the table 81 , its position is determined solely by that of the spindle drive 83 , since the force in question is not sufficient, the positions of the pistons 51 and 52 relative to the cylinder 49 change. This means that the table 81 does not move until the force f reaches a certain larger value.

However, if a sufficient force, for example to the right, is exerted on the table 81 to overcome the hydraulic pressure in the chamber of the cylinder 49 containing the piston 51 , then the pressure escapes via the line 55 into the energy accumulator 48 while the piston 51 follows moves to the right, so that the distance between the two pistons 51 and 52 shortens. If the spindle drive 83 is at a standstill, the table 81 can move to the right. In summary, this means that the table can move to the right as soon as an external force exceeds the set value. At a suitable point in the area of the cylinder 49 , a Fühleinrich device responsive to any change in the distance between the two pistons 51 , 52 can be arranged, which immediately generates a signal to immediately stop the machine tool at the start of the movement of the table 81 .

In the following, the application of the safety system according to the invention in connection with an automatic tool change function in a machine tool is considered. In a production line or the like. Working machine tools are necessarily equipped with an automatic tool changing device, since different tools to be carried out by the machine require different tools. The various tools used for the individual machining operations are exposed to different forces from different directions during operation. Accordingly, the values + f ₀ and - f ₀ for the safety system used on the machine tool in question must be reset each time the tool is changed.

Fig. 25 shows a block diagram of an operating with automatic tool change, and equipped with a safety system machine tool. In normal operation, the machine tool is controlled by an NC control unit 84 . A program COM containing the necessary data for all machining operations is entered from outside the NC control unit 84 , which on this basis uses a motor 85 for driving in two directions along the X , Y and / or Z axis Control signal S ₁ controls. An automatic tool changing device ATC 86 is provided for the selection of the tools to be used by the machine tool.

A safety control unit 67 is necessary for the use of a safety system on such a machine tool. The value f _{0 of} a force at which the safety system is to respond is input to the safety control unit 67 by the NC control unit 84 and then determines the response behavior of the safety system. If a fault occurs with the effect of a force exceeding the set value on the force element, e.g. B. a machine table of the machine tool, the safety system according to the Invention generates an emergency stop signal S ₃ , which flows to the NC control unit 84 .

The emergency stop signal S ₃ reaches the highest point in the hierarchy of the NC control unit 84 in order to stop the machine tool in a state as close as possible to the starting position of the NC program. Because of its inertia, the machine table carrying a workpiece initially necessarily moves on. This movement of the table, which continues after the generation of the emergency stop signal S ₃ , is absorbed by storing the kinetic energy of the table by the deformation of the spring present in the energy store 48 . In the safety system used here, the force + f ₀ or - f ₀ , which triggers the system, is adjustable depending on the type of tools used and the machining operations to be carried out with them.

An embodiment of a machine tool equipped with a hydraulically operating safety system is shown in a schematic form in FIG. 26. The machine tool has an upright column 88 , on which a working head 89 can be moved up and down. The working head 89 includes a motor 90 and a tool holder 91 attached to a spindle, in which a tool, e.g. B. a drill or a milling tool is used to transmit power. The direction of movement of the working head 89 runs along the Z axis. The column 88 is connected at its lower part to a base 93 . This carries a base frame 94 , which can be moved horizontally by means of a spindle drive 83 and carries a machine table 81 . Extending the direction of movement of the undercarriage 94 lot right to the drawing plane along the Y axis, and then the machine table 81 is moved to the right and left-voltage level in the drawing along the X axis. For aligning the table 81 in the machine tool, a spindle drive 83 is arranged between it and the base frame 94 .

A workpiece 95 is clamped on the machine table 81 and can thus be moved along the X axis and the Y axis in cooperation with the base frame 94 . The attached to the working head 89 and rotatable tool 92 can be brought into the desired position by moving the working head vertically. In the described machine tool, one of three actuating elements 47 between the working head 89 and the column 88 , between the base 94 and the base 93 and between the base 94 and the table 81 is net angeord.

The actuating element 47 arranged between a running nut 96 of the spindle drive 83 and the table 81 has a hydraulic cylinder of special construction in the form of a cylindrical hollow body with a spindle arranged therein.

The hydraulic connections of the three actuating elements 47 are connected together to a force accumulator 48 arranged separately therefrom, the structure of which is shown in FIGS. 18 and 24. The hydraulic motor 68 of the force accumulator 48 can be actuated in accordance with the NC program in order to adjust the force f to which the actuating elements 47 respond, for example to 100 kgf, 500 kgf or 1000 kgf. The forces to which the actuating elements 47 are to respond are set in accordance with the values determined for the individual tools to be used in the NC machine tool.

In the above-described embodiments of the The security system according to the invention is carried out the force effective in the movements of a force element by springs, hydraulic or pneumatic pressure, whereby the system in any case at least one compression spring for Saving and / or adjusting the effective force contains. The following is the mode of operation of a hydraulic pressure instead of a safety system using a spring explained.

Fig. 27 shows in a simplified illustration of the construction of an actuator 47 having a cylinder 49 and two pistons 51, 52. Fig. 28 shows another embodiment 99 with a double piston 97 and two cylinders 98,. The operation of these two embodiments of the security system corresponds to that of the embodiment shown in FIG. 5. If a force of a force element acting in one direction or the other on the actuating element according to FIG. 27 exceeds the previously set value, then the distance between the two pistons 51 and 52 increases or decreases. In the embodiment according to FIG. 28, there is a corresponding increase or decrease in the distance between the connection flanges 100 and 101 present on the cylinders 98 , 99 .

The sensors or other components for the generation an emergency stop signal when a force occurs element, e.g. B. an effective machine table Malfunction does not necessarily have to be in or on the respective Cylinder may be arranged. In any case, however more responsive to every movement of the movement element Sensor or the like at a suitable point in the area of the cylinder can be provided.

The actuating element 47 can be arranged in the manner shown in FIG. 26, between the spindle drive 83 and the movable table 81 of a machine tool or the like. When using an actuator 47 with two pistons 51 , 52 of the type shown in FIG. 27, the safety system used in a machine tool works satisfactorily, but the actuator 47 shown in FIG. 27 has relatively large dimensions and is therefore difficult to install. In addition, the actuating device 47 with the pistons 51 and 52 is arranged eccentrically with respect to the axis of the spindle drive 83 , so that difficulties can arise due to the off-centered attack of forces. In the preferred embodiment of the actuating element shown in FIG. 28, the pistons are therefore arranged concentrically with the spindle drive 83 .

The double piston 97 shown in FIG. 28 can also be hollow; Fig. 29 shows such a Actuate the restriction member 47 having a hollow double cylindrical piston 102. When the forces exceeding the respectively set value are exerted on one of the two cylinders 103 or 104 , the oil contained in the relevant cylinder is displaced therefrom, the distance between the flanges 105 and 106 formed on the cylinders changing accordingly. Details of a practical implementation of the principle explained with reference to FIG. 29 are shown in FIG. 30.

Figs. 31 to 33 show various embodiments of in connection with in FIG. Actuator shown 30 47 usable means for generating a trigger signal for actuating the safety system. These devices each include an arrangement of microswitches 107 responsive to movement. In the embodiment according to FIG. 31, a microswitch 107 is arranged between a web of the piston 102 and an end wall of the associated cylinder 103 or 104 . In the embodiment shown in FIG. 32, a microswitch 107 attached to a cylinder 104 has an actuating member with a roller 109 , which is supported on a bar 108 having a notch on an axially attached to the other cylinder 103 . When the distance between the two cylinders 103 , 104 changes , the roller 109 comes into and out of engagement with the notch, so that the microswitch 107 is opened and closed. In the embodiment according to FIG. 33, an actuating element 47 includes a double piston 102 , a flange 110 projecting thereon and two microswitches 107 arranged in an active position between the cylinders 103 and 104 and the flange 110 .

Instead of the microswitch 107 , simple break contacts in connection with relays can also be used to generate corresponding signals. The signals generated do not need to be limited to the digital ON and OFF signals which are inevitably only generated when interrupter switches and the like are used. For example, it is also possible to use a position detector that works with a Hall effect element, which generates an analog signal when the Hall effect element approaches a magnetic field, which is then compared to a threshold value in order to generate a trigger signal for actuating the safety system.

Fig. 34 shows an embodiment of a hollow actuating element 47 which, for example, between the spindle drive and the machine table. B. a machine tool is net angeord. The spindle 83 of the spindle drive is here surrounded by two annular cylinders 103 , 104 and a piston 102 designed as a hollow body. The cylinders have cavities filled with oil, and the piston 102 is guided in the right cylinder 104 . To simplify the construction of the device, O-rings are used at all points to be sealed. In practical operation, there is no constant sliding movement between the piston 102 and the cylinders 103 , 104 , but only when the safety system comes into effect, so that the sealing presents no difficulties over a long period of time.

The cylinder 103 acting as a moving element is connected at its left-hand free end to a machine table 81 acting as a force element of a machine tool. When the table 81 is moved to the right, the cylinder 103 is correspondingly moved to the right. The spindle 83 is rotatably mounted on the base 94 by means of a bearing (not shown) and can be rotated by a motor. The device used in the embodiment according to FIG. 34 for generating a signal indicating the response of the actuating element 47 corresponds to the embodiment shown in FIG. 33. In Fig. 34 it can be seen, the spatial arrangement of a projecting arm 104 on the cylinder 112, a piston 102 protruding on the bar magnet 113 and a continuous relative to each other from the arm 114 from the other cylinder 103. Attached to arms 112 and 114 are induction or proximity switches 111 , each containing a coil, which responds to movements relative to magnetic rod 113 .

Fig. 35 shows an embodiment of an energy accumulator 48, by means of which the hydraulic pressure in the safety system can be adjusted in each case to a fixed value. The Darge illustrated energy accumulator has two end plates 115 , 116 , which are interconnected by four lag screws 117 . The lag screws 117 also serve the displaceable guidance of two spring plates 118 , 119 , between which a compression spring 60 is held under compression. A hydraulic cylinder 56 with a piston with a short stroke is inserted between the displaceable spring plate 118 and the end plate 115 . The spring plate 119 is connected to the other end plate 116 via a spindle 251 having a trapezoidal thread, which can be set in rotation by a hydraulic motor 68 arranged outside. The hydraulic motor 68 is actuated via a safety control unit in accordance with the force to be set for different tools. The position of one end of the compression spring 60 can be changed by actuating the hydraulic motor.

If the force to be absorbed by the actuating element 47 is to be set to 100 kgf, 500 kgf or 1000 kgf, the opening and closing actuation of a proximity switch arranged above the spring plate 119 takes place. It is also possible to use a motion detector or the like. B. a magnetic scale, etc., for measuring the distance between the spring plate 119 and the end plate 116 , so that the hydraulic motor 68 can be combined with a servo system within the safety system.

In the described Druckspeicehr 48 , it is not necessary that the hydraulic motor 68 is constantly in operation for the generation of hydraulic pressure. Since there is no oil circulating in the hydraulic pressure circuit, the value set for the respective force remains unchanged after the position of one end of the spring 60 is first set by means of the threaded spindle 251 and the spring plate 119 . In the event of a power failure, the safety system works to ensure or relieve the machine tool. In the case of a processing system with a conventional security system, on the other hand, it is necessary to send the security system a special command when any malfunction occurs, which results in a very low reliability of the known security system. In contrast, an important feature of the safety system according to the invention is that an energy required for the response of the system remains stored within the hydraulic pressure circuit after the force required for the response of the system has been set.

Fig. 36 shows a group of characteristic for a practical execution of the safety system according to the invention, static force / displacement relationship. The relationships represented by lines 1, 2 and 3 each comprise a neutral area and a range of motion, from which it can be seen that the respective movements take place in a proportional relationship each time the force f increases. This proves that the security system safely fulfills the specified and expected functions. The values f 1 , f 2 and f 3 for the force to which the safety system responds can be set safely and precisely by operating the hydraulic motor 68 accordingly.

Fig. 37 shows dynamic characteristics of the safety system, which each involve a certain delay TX n. In the figure, TX ₁ denotes the delay from the moment when a force acting on the safety system reaches the set value until the generation of the corresponding function signal, TX ₂ denotes the delay from the generation of the signal until it follows an amplification Transmission, TX ₃ denotes the delay from the reception of the function signal by the NC control unit to the triggering of the emergency stop function, and TX ₄ denotes the delay occurring due to inertial forces in the machine tool.

If one compares the characteristics shown in Fig. 37 with the operating speed of a machine tool when machining a workpiece, it can be seen that the safety system comes into operation after moving the table over a distance of 5 mm or less. The practical design of the actuating element is based on a freedom of movement of +/- 10 mm, the respective movement element having a freedom of movement of +/- 5 mm. Overall, this results in freedom of movement of (5 mm + 5 mm) + (10 mm + 10 mm) = 30 mm.

In this context it should be noted that the dynami characteristics of the system not only through the System inherent delays are determined, but also the influence of the rigidity of parts of a tool machine in which the safety system is installed, subject to. The machine table has one, for example Rigidity of 1 µm / 500 Newtons, while its rigidity after installation of the safety system in the machine tool Is 1 µm / 150 Newtons. However, it should be noted here that with a proper design and more precisely Machining the connector between the actuation element and an outer part and the surface quality the connector inside the actuator only a slight impairment in the rigidity at the Use of the security system results. This is a essential aspect in the manufacture of tools machinery.

Fig. 38 shows time-related characteristic force / displacement curves when using the above-mentioned machine tool for machining workpieces, the time being plotted on the abscissa and the forces and movements on the ordinate. In the present case, a workpiece is machined horizontally using a face milling tool. If a fault occurs at a time T ₁ , whereupon the load increases to f ₀ + Δ f , then the safety system responds with a delay Δ t ₁ , so that the corresponding movement begins at a time T ₂ . From this point in time T ₂ , the movement and the force increase steadily until after a delay Δ t ₂ a stop signal is generated at a point in time T ₃ , whereupon a slowdown occurs at a point in time T ₄ until the machine at a point in time T ₅ comes to a standstill and the movement and strength then no longer increase.

In the practical implementation of such a tool machine is the time period from the activation of the safe system on the increase in force above the set value until the plant comes to a complete standstill in Range of about 100 ms. Then the milling machine without damaging the milling tool Continuation of what has started or to initiate a fol be approached to the processing step, from which can be seen that the security system according to the invention works effectively and reliably.

At the above-mentioned processing plant Loads of 100 kgf, 500 kgf and 1000 kgf adjustable. The lowest load can never be less than 100 kgf sink, because between the sliding surfaces an O-ring is inserted in the cylinder and piston, so that there is a frictional resistance between the correspondingly more neutral sliding surfaces Area results.

In the machine tool described above, the Working head usually a fairly large weight and one correspondingly strong inertia, so that with a small and light tools for a very small load put security system not sufficiently reliable can work. In this case, use is recommended of the safety system for low loads as in described below.  

Fig. 39 shows a machine tool with a in the plane of the X and Y axes to the right and left or forward and backward movable machine table 120 and a tool holder 121 movable up and down along the Z axis with a safety function for the up - and downward movement of a tool 92 . The machine table 120 here uses a spring to absorb the forces exerted on the table from the outside. The combination of the table 120 provided with a safety function and the tool holder 121 provided with a safety function enables the use of the safety system designed in this way for low loads of, for example, 50 kgf and 20 kgf, in particular also of 1 kgf.

Further embodiments of machine tables provided with safety devices are shown in FIGS. 40 to 44 and FIGS. 45 to 48. The embodiment of FIG. 40 to 44 is formed so that it is responsive to a set value in excess force. The machine table 120 shown includes a base plate 122 , a slide 123 and a table 81 which acts as a force element. Linear guides 124 and 125 are installed between the table 81 and the carriage 123 and between the latter and the base plate 122 , so that the table 81 can be moved in the direction of the X- axis and the Y- axis.

As can be seen in particular in Fig. 42, at least one actuating element 47 with a double piston and two cylinders is built in between the table 81 and the carriage 123 . The actuating element 47 essentially has the structure shown in FIG. 10. The operating principle of the actuating element 47 is shown in FIG. 44. Little least one of the actuating element 47 associated micro switch or proximity switch is used to detect movements of the double piston relative to the cylinders.

The forces exerted on the table 81 in the direction of the X axis and the Y axis are absorbed by compression springs 30 and 31 of the respective actuating elements 47 . After installing the compression springs 30 and 31 , the value set for the force to be absorbed can no longer be changed. This is because it is extremely difficult to incorporate movable means for adjusting the compression springs 30 and 31 within the actuators 47 , since the linear guides 124 and 125 are arranged outside the actuators 47 with their springs 30 , 31 and the latter are therefore inaccessible. These difficulties are eliminated in the embodiment according to FIGS. 45 to 48 in that this embodiment enables the set values to be changed.

In the embodiment shown in FIGS. 45 to 48, linear guides 124 and 125 are each arranged further inside between the table 81 and the carriage 123 or between the latter and the base plate 122 , while four actuating elements 47 each having two cylinders and a double piston further out on the four sides of the table. Such actuators equipped with compression springs 30 and 31 and operating in multiple stages are described in Japanese Patent Application Sho 62 (1987) -2 03 929 by the applicant. In this actuator two similar compression springs 30 and 31 are used on the pressure side and on the tension side, respectively, the springs being adjustable so that they work in different ways. For this purpose, the output voltage of the compression springs 30 and 31 can be adjusted from the outside by means of screws 126 and 127 shown in FIG. 48, which leads to a corresponding setting of the values for the forces to be absorbed. Instead of the screws 126 and 127 , hydraulic servomotors, which can be controlled by the safety control unit, can also be used to set the compression springs 30 and 31 .

Instead of springs, a combination of an energy accumulator and a hydraulic or pneumatic pressure circuit can also be used to absorb and transmit external forces. Fig. 49 and 50 each show another embodiment of an operating with a hydraulic pressure circuit control element 47, wherein the and which has in Fig. 49 Illustrated a double piston and two cylinder in Fig. 50 Shown two piston and a cylinder. In these figures, the respective cylinders are designated 133, 134 and 135 and the pistons 135 to 137 .

Fig. 51 shows a Ausfürungsform of having a safety function-equipped tool holder 121 of FIG. 39,

with a piston 128 , which retracts into a housing 91 under the action of a force which is directed upwards and exceeds a set value. The resulting opening or closing actuation of a microswitch 130 causes a change in the inductance of a coil 131 surrounding the housing 91 . Due to this change in inductance, one of the coil 131 arranged opposite detector coil 132 generates a signal which is applied to the NC control unit of the machine tool via the safety control unit in order to interrupt the operation of the machine tool. The movements of the piston can also be detected by means of a piezoelectric proximity switch or a magnetic switch working with Hall elements. The transmission of the signal vo from the rotating tool holder 121 to the fixed parts of the system can take place via a frequency modulation system or an optical system instead of the above-described inductive connection.

By combining the above-described tool holder 121 having a safety function with the previously described machine table 120 provided with safety devices in a machine tool, a full safety system is obtained which can be adapted to a very wide range of loads, including very small loads.

The security system 25058 00070 552 001000280000000200012000285912494700040 0002004000948 00004 24939m according to the invention with its actuators supply elements, energy stores, etc. is above in Relation to its use in a facility for the machining of workpieces or in one  Machine tool described, but it is obvious also for other processing systems or machine tools usable, e.g. B. in a feed device Machine tool or any other equipment. Further can the security system described also z. B. between a machine tool and one in a manufacturing plant can be used with this interacting robot. So can such a security system be in the range of Gripping a robot or in the area of a table can be used on which a workpiece is clamped.

Fig. 52 shows an embodiment of a device for measuring shaft shear with a safety system according to the invention. The expression shaft thrust here denotes a force exerted in the axial direction on a shaft or a table, which force can be measured by means of measuring cells installed in a machine tool.

Such a wave thrust measurement is. e.g. B. applied to breakage or other damage to workpieces, To prevent tools or parts of a machine tool. In a conventional arrangement for the shaft thrust measurement is a measuring element, e.g. B. a strain gauge, on a moving part of a machine tool, e.g. B. on a spindle or shaft or a machine table brings and generates one of the respective shaft thrust speaking signal.

In conventional devices for shaft shear measurement there is the disadvantage that in addition to the actual Shaft shear force certain external interference on the Act device, caused for example by the drive of the machine, such as the main drive motor or a feed motor, and through the drive transmission, like a gear transmission. This makes it extremely difficult to measure and correspond to the thrust exactly and correctly signals between a moving part and the itself to transfer rotating shaft.

For a shaft thrust measurement is a six-component measuring device or a six-component measuring table working with piezoelectric elements and strain gauges, which or which measures linear forces acting in the direction of the X , Y and Z axes as well as torsional forces occurring around these axes. Such a six-component measuring table is known to be suitable for small and medium-sized systems, but not for measuring very large shaft shear forces and loads. In addition, the conventional shaft thrust measuring method working with a six-component measuring table can only be carried out independently of the machining operation of a machine tool. Accordingly, the assembly of a six-component measuring table on a machine tool is extremely cumbersome, and it is also not possible to carry out a shaft thrust measurement in parallel with the machining operation of the machine in order to be able to change the working conditions in accordance with the result of the measurement.

The one formed according to the present invention Wave thrust measuring device enables the actuation of the Safety system of a tool described above machine when on the moving part of a force elements, e.g. B. a table or a spindle or shaft the machine tool, the shaft thrust exerted previously set values, and the correct and exact determination of the shaft thrust by means of a measurement cell without any interference, the free choice of Setting value of the force at which the Security system takes effect, and constant measurement and monitoring the operational forces in relation to to a given force.

When a measuring element for measuring a force is installed in a machine tool, the load to be determined is usually concentrated in the measuring element, which can lead to its destruction. By the combination of such a measuring element, for. B. a load cell, with the safety system according to the invention and by setting the force + f ₀ or - f ₀ , to which the safety system responds to a value below the maximum load of the measuring element, it is therefore possible to provide a device for the to constantly monitor a force without destroying the measuring element or the measuring cell.

The embodiment of a shaft thrust measuring device shown in FIG. 52 comprises an actuating element 47 of the type shown in FIG. 34 and a load measuring cell incorporated therein. In Fig. 52, the embodiment of Fig. 34 corresponding parts with the same reference numerals as there and are not described again. The following description thus relates solely to other parts or parts not shown in FIG. 34.

In the actuating element 47 shown in FIG. 52, the cylinder 103 is arranged essentially fixed relative to the linearly movable table 81 . In the cylinder 103 , a load cell is used in the manner described below.

In the outer peripheral surface of the cylinder 103 , a wide groove 210 is formed, on the center of which a narrow groove 211 formed in the inner peripheral surface of the cylinder is aligned. At 90 ° to each other in the circumferential direction, four strain gauges 212 are BEFE Stigt on the bottom surface of the outer wide groove 210 . Furthermore, the wide outer groove 210 contains an inner filling 213 made of z. B. silicone rubber and an outer filling 214 of z. B. oil-resistant silicone foam rubber or the like .. The two grooves 210 and 211 are separated by a thin wall 215 , which is effective as part of a load cell. The width L _{1 of} the outer groove 210 is, for example, 3 mm, the width L _{2 of} the inner groove 211 is approximately 1 mm, and the thickness d of the thin wall 215 is approximately 0.5 mm.

The mode of operation of the shaft thrust measuring device is explained in the following with reference to FIGS . 53 to 57. Fig. 53 shows a machine tool in the housing of a main bearing od. The like. Disposed shaft thrust-measuring device. A plurality of bearings 217 are arranged at axial intervals on a shaft 216 which represents a linearly movable part.

Inner spacer rings 218 and outer spacer rings 219 , 220 are inserted between the bearings 217 . A longer cylindrical spacer sleeve 223 is inserted between the inner ring 221 of the uppermost bearing 217 and a head piece 222 of the shaft 216 .

A housing 224 which accommodates the bearings 217 , the spacer rings 218 to 220 and the spacer sleeve 223 has an annular stop 225, which can be fastened on its upper inner edge, for the outer ring 227 of the uppermost bearing 217 . The stop 225 can be fastened to the upper inner edge of the housing 224 by means of screws 226 .

Between the outer ring 227 of the uppermost bearing 217 and the stop 225 , an annular shaft thrust measuring device 228 representing a load cell is inserted. By tightening the annular stop 225 , the measuring ring 228 is held in fixed contact with the top bearing 217 .

The formation of the annular measuring cell 228 can be seen in detail in FIG. 54. A wide groove 230 is formed in the axial center of the outer peripheral surface of the annular body 229 of the measuring cell 228 . Further, a narrower groove 231 is formed in the axial center of the inner peripheral surface of the annular body 229 , and four strain gauges 232 are attached to the bottom surface of the wide outer groove 230 at circumferentially offset positions by 90 °. To protect the strain gauges, the groove 230 contains a filling 233 made of silicone rubber.

FIG. 55 shows an enlarged illustration of the detail denoted by a in FIG. 54. With a diameter D = 80 mm of the annular shaft shear measuring cell 228 at the bottom of the outer groove 230 ( FIG. 54), the width L _{1 of} the groove 230 is 4 to 5 mm, the width L _{2 of} the inner groove 231 is 1 mm and the wall thickness d between the two grooves 230 and 231 0.5 mm.

The shaft thrust measuring ring 228 is arranged so as to be stationary relative to the shaft 216 in the axial direction and is linearly movable together with the latter. The relationship between the shaft 216 shown in FIG. 53 and the associated bearing 217 can be understood as a model of a spring system shown in FIG. 56. If an axial force is exerted on the shaft 216 shown in FIG. 53, the bearing 217 is elastically deformed; this corresponds to an elastic deformation of springs 401 , 402 shown in FIG. 56, each of which has a spring constant k ₁ or k ₂ . Fig. 56 shows the shaft in the form of a movable part 501 and a substantially static system 601 corresponding to the outer spacer rings 219 and 220 ( Fig. 53) which axially form the bearing 217 (the springs 401 , 402 ) in contact with the ring Load stop 225 .

In this model, a force f ₀ initially acts on the shaft 501 so that it is held in a stable position. If a shaft thrust force f _ex is now exerted on the shaft 501 from the outside in the direction of the arrow b shown in FIG. 56, then this force f becomes active in two mutually opposite directions Δ f ₁ and Δ f ₂ ( FIG. 57 ) disassembled, which are taken up by the springs 401 and 402 . Accordingly, the spring 401 deforms by an amount Δ x corresponding to a deformation characteristic X _{1 of} the spring constant k ₁ , while the other spring 402 deforms by an amount Δ x corresponding to a deformation characteristic X _{2 of} the spring constant k ₂ . The deformation by the amount Δ x is to be understood here as the compression deformation of the spring.

The relationship between the shaft shear force f _ex , the spring constants k ₁ , k ₂ and the deformation Δ x can be seen from the following equation:
f _ex = Δ f ₁ + Δ f ₂ = k ₁ Δ x + k ₂ Δ x = ( k ₁ + k ₂ ) Δ x .
When using this equation, the force f _ex results from the deformation Δ x of the springs 401 and 402 , provided that their spring constants k ₁ and k _{2 are} known. It can be seen in FIG. 56 that the amount of deformation Δ x can be detected from the side of the essentially static system 601 .

The measurement of the amount of the deformation Δ x in the above-described model of the side of the substantially static system 601 here corresponds to a measurement of the load on the bearing 217 of the side of the substantially static system 601 ago. The measurement of the load on the bearing 217 at the point at which the shaft thrust measuring ring 228 is arranged in the essentially static system 601 ( FIG. 53) thus makes it possible to determine the shear force acting on the shaft 216 .

As shown in FIG. 53 and described above, the shaft thrust measuring ring 228 is held under a certain preload by the annular outer stop 225 . In this state, the shaft thrust force acting on the shaft 216 is transmitted through the spacer sleeve 223 to the inner ring 221 of the uppermost bearing 217 , whereupon some of the force is further transmitted to the inner ring 221 of the next bearing 217 and so on.

The remaining portion of the shaft thrust transmitted to the inner ring 221 of the top bearing 217 is thus from the rolling elements or balls of this bearing 217 on its outer ring 227 and from this via the outer rings 227 of the underlying bearing 217 and the outer spacer ring 219 to the outer ring 227 of the lowest camp.

As a result, one of the complementary reaction forces acting on the outer ring 227 is exerted on the shaft thrust measuring ring 228 , which is always loaded in contact with the outer ring 227 of the uppermost bearing 217 , so that a tension builds up in the thin wall 234 and the strain gauges graze 232 on the shaft thrust force generate corresponding electrical signal on shaft 216 .

In the arrangement of the shaft thrust measuring ring 228 shown in FIG. 53 directly below the outer annular stop 225 , the electrical output signal of the strain gauges 232 can be tapped effortlessly from the outside of the spacer sleeve 223 . The shaft thrust measuring ring 228 does not necessarily have to be arranged at the location shown in FIG. 53, but can also be used at the location of one of the outer spacer rings 219 or 220 , as long as the reliable tapping of the aforementioned electrical signals is ensured.

The shaft thrust measuring device can be installed in running nuts which are in engagement with threaded spindles which extend along the X , Y and Z axes of a machining system. Fig. 58 shows the installation of a shaft thrust measuring device in the running nut 235 of a threaded spindle 83 for the linear movement of a table 81 in the direction of the X axis. In this case, the running nut 235 is a stable system relative to the linear direction of movement of the table 81 .

As can be seen in FIG. 58, the running nut 235 is in threaded engagement with the spindle 83 and is fixedly connected to an arm 236 protruding from the table 81 by means of a union nut 237 .

In the central region of the outer circumferential surface of the barrel nut 235 , a wide groove 238 and opposite it a narrow groove 239 in the central region of the inner circumferential surface is formed. At the bottom of the outer groove 238 , four strain gauges 240 are fastened at locations offset by 90 ° to one another in the circumferential direction. As can be seen in the enlarged illustration shown in FIG. 59 of the detail designated by b in FIG. 58, the wide outer groove 238 and the narrow inner groove 239 are separated from one another by a thin wall 241 . The outer groove 238 , in which the four strain gauges 240 are fastened, contains an inner filling 242 made of silicone rubber and an outer filling 243 made of an oil-resistant silicone foam rubber or the like. As indicated in FIG. 59, the thickness is d thin wall 241, for example 0.5 mm, the width L _{2 of} the inner groove 239 about 1 mm, the corners 244 between the bottom and the walls of the inner groove 239 being rounded off with a radius of 0.2 mm.

In the embodiment of the invention shown in FIG. 58, the running nut 235 itself represents a load cell for measuring a shaft thrust force in the direction of the X- axis of the table 81. When the spindle 83 rotates, the running nut 235 moves along it and thereby takes over the arm 236 along with the table 81 in the direction of the X axis. If the frictional resistance occurring in the bearings supporting the table is assumed to be neglected, it is possible to measure the forces occurring on the table 81 in the direction of the X axis correctly and precisely by means of the running nut 235 designed as a load measuring cell. When stresses occur in the thin wall 241 of the load measuring cell due to forces exerted by the arm 236 of the table on the running nut 235 , the strain gauges 240 generate one of the shaft thrust forces exerted by the table 81 on the running nut, which acts as an essentially static system electrical signal.

In a modification of the shaft thrust measuring device shown in FIG. 52, a load measuring cell can be arranged at a location corresponding to the arrangement of the load measuring cell in the running nut 235 shown in FIG. 58. Such a load cell can be arranged, for example, at the position of the piston 102 designated by c in FIG. 52 or at the position designated by e of the cylinder 104 .

The essentially static system in the shaft thrust measuring device shown in FIG. 52 enables the shaft thrust force of the table 81 to be measured, since the thin wall 215 of the load cell is deformed or deformed in accordance with the force of the linearly movable table 81 acting in the direction of the X axis is so that the strain gauges 212 produce an electrical output signal proportional to the shaft thrust. The shaft thrust force to be measured by means of the shaft thrust measuring device is equal to the force exerted on the actuating element 47 by the table 81 acting as a force element. Accordingly, it is possible to vary the force to be stored in the force accumulator shown in FIG. 26, that is to say the force to which the safety system is to respond, on a real-time basis in accordance with the shaft thrust force. As a result, it is not only possible to continuously monitor the axial reaction forces occurring during machining, it is also possible to provide a safety system that works with the most favorable setting value at all times.

The shaft thrust measuring device described above can not only be used to measure the shaft thrust force of the table 81 , but can also be used in combination with the actuating element 47 in the column 88 shown in FIG. 26. In general, the shaft thrust measuring device can be used to determine shaft shear forces on a wide variety of linearly movable elements or assemblies. A system designed according to the possibilities indicated above can in this way cause a machine, e.g. B. a machine tool, each performs an evasive movement as soon as a moderately large force acts on them. This is done by measuring a shaft thrust force occurring in the machine by means of the shaft thrust measuring device and correspondingly controlling the feed or the rotation of the respective moving part on a real-time basis in cooperation with the safety system.

As can be seen from the above description, the safety system according to the invention responds to the action of a force f exceeding a set value on a part belonging to a production system or to a machine tool and causes the relevant part to evade the excessively large force, thereby to prevent the relevant part or other parts of the machine tool from being damaged and as a result of which the entire machining or production system comes to a standstill. When the safety system according to the invention is used on a table and a tool holder of a machine tool, the possibility of bringing the operation of the machine tool to a standstill at short notice provides increased security.

The operations that together form the security system elements and energy storage have a very simple one Construction, so that the security system economical can be represented. In addition, the security system versatile because it effortlessly fits into existing ones Machine tools and other machines and systems can be installed.

The shaft thrust measuring device according to the invention enables also measuring one of a force element of the safe system on a moving element waves thrust. In this way it is possible to work at a machining shear force constantly occurring monitor and force, especially the wave thrust force to which the security system should respond, each set to the cheapest value.

Because the shaft thrust measuring device inside the actuator elements, in the housing of a shaft or spindle or in the A nut of a spindle drive can be installed, there is no need for considerable construction work a six-component measuring table for each measurement of Shaft thrust.

The shaft thrust can occur during operation Machine tool can be constantly measured so that it is possible is the working conditions etc. quickly at any time adjust measured shaft thrust so that a powerful and extremely precise machining system results.

There is also the possibility to differentiate under where working conditions occur on a moving part forces related data to save them using the Analyze computer of an NC machine tool or the like and from this the service life or the time at which the work breaks to testify in advance. In other words, it enables the use of a tool's stored data  machine, the most favorable working conditions independently determine and adjust what last finally to the possibility of a self-learning work leads machine.

Although preferred embodiments of the Invention have been described in detail, the Structure and the arrangement of the parts of this execution shape within the scope of the inventive concept and the claims can be modified in different ways.

Claims (8)

1. Full safety system, characterized by at least one under the action of one of a movable force member (eg. B. 81) exerted on it, a set value (f ₀₎ over increasing force (f) in the direction of the force movable moving element (1, 5, 7 ), by at least one static element ( 6 , 8 ) determining the starting position of the movement element and by at least one force transmission element ( 9 , 10 ) connected to the static element and the movement element for exerting a force, the system for stopping the Movement of the force element responsive to movement of the movement element by a fixed amount. 2. Full security system in one of a (z. B. 81) by at least under the action of a movable force element applied to it, a set value (f ₀₎ over increasing force (f) in the direction of the force movable moving element (49, 51 ), by at least one static element ( 52 ) determining the starting position of the movement element and by at least one force transmission element ( 151 , 152 ) connected to the movement element for exerting a magnetic force on the static element, the system for stopping the movement of the force element a movement of the movement element responds by a fixed amount. 3. actuating element, characterized by at least one under the action of one of a movable force member (eg. B. 81) exerted on it, a set value (f ₀₎ over increasing force (f) in the direction of the force movable moving element (1, 5, 7 ), by at least one static element ( 6 , 8 ) determining the starting position of the movement element and by at least one force transmission element ( 9 , 10 ) for exerting a force on the movement element and the static element. 4. Energy storage device, characterized in that it is connected to an actuating element ( 47 ) which has at least one force ( f ) in the direction exerted on it by the action of a movable force element ( 81 ), a set value ( f ₀ ) the force-movable movement element ( 49 , 51 ) has at least one static element ( 52 ) determining the starting position of the movement element and a hydraulic or pneumatic pressure circuit ( 55 ) effective as a force transmission element for exerting a force on the movement element and the static element, and that the energy accumulator ( 48 ) has an elastic element ( 61 ; 63 ) for storing a force transmitted to it via the hydraulic or pneumatic pressure circuit. 5. Machine tool, characterized by an actuating element ( 47 ) with at least one force ( f ) in the direction of the force-movable movement element (exerted on it during operation by a movable force element ( 81 ) that exceeds a set value ( f ₀ ). 49 , 51 ), a static element ( 52 ) determining the starting position of the movement element and a hydraulic or pneumatic pressure circuit ( 55 ) effective as a force transmission element for exerting a force on the movement element and the static element, and by a force accumulator ( 48 ) for storing a force transmitted to it via the hydraulic or pneumatic pressure circuit in an elastic element ( 61 , 63 ), movement of the movement element being detectable by a fixed amount and evaluable for stopping the movement of the force element. 6. Full security system, characterized by at least one under the action of a from a movable table ( 81 ) exerted on it, a set value ( f ₀ ) exceeding force ( f ) in the direction of the force movable movement element ( 49 , 51 ) by a static element ( 52 ) determining the initial position of the moving element and by a force transmission element for exerting a force on the moving element and the static element for stopping the movement of the movable table. 7. full security tool holder, characterized by under the action of a force exerted by a movable tool (92) on it, a set value (f ₀₎ over increasing force (f) in the direction of the force movable moving element (128) by the initial position of the moving member determining static element ( 91 ) and by a force transmission element ( 129 ) connected to the movement element for exerting a force on the movement element and the static element,
wherein a movement of the movement element can be detected by a fixed amount and can be evaluated to stop the movement of the tool. 8. Fully security system with a force ( f ) in the direction of the force movable movement element ( 102 , 103 ) exerted on it by a movable force element ( 81 ) exerted on it, a set value ( f ₀ ), the initial position of the movement elements-determining static element ( 104 ) and a force transmission element connected to the movement element for exerting a force on the movement element and the static element, in which movement of the movement element can be detected by a fixed amount and evaluated for stopping the movement of the force element, characterized in that the system further comprises a shaft thrust measuring device formed from an actuating element ( 47 ) comprising the moving element and the static element and a load measuring cell ( 210-215 ), in which the load measuring cell for measuring a force element moving from the moving element to the moving element nt applied shaft thrust is formed and arranged.