Clamping drive and method for operating a clamping drive

Abstract

The invention relates to a clamping drive (1) with a first jaw carrier (2) and a second jaw carrier (3), wherein the first jaw carrier (2) and the second jaw carrier (3) are connected to a drive spindle (5) in such a way that they can be moved translationally relative to each other by the drive spindle (5), wherein the first jaw carrier (2) is fixed to a lower part (4).In a clamping drive (1) that enables the monitoring of the force currently applied to a workpiece, it is provided that a force measuring module (9) is connected to the drive spindle (5), that the force measuring module (9) has at least one measuring element (10) for detecting tensile and / or compressive deformations, that the force measuring module (9) includes an evaluation unit (11), and that signals from the measuring element (10) can be received by the evaluation unit (11), whereby information regarding a force applied to the force measuring module (9) can be determined by the evaluation unit (11) depending on the signal from the measuring element (10).

Description

[0001] The invention relates to a clamping drive with a first jaw carrier and a second jaw carrier, wherein the first jaw carrier and the second jaw carrier are connected to a drive spindle in such a way that they can be moved translationally relative to each other by the drive spindle, wherein the first jaw carrier is fixed to a lower part.

[0002] In addition, the invention relates to a method for operating a clamping drive.

[0003] Clamping drives, particularly for vises, are known in the art in a variety of designs. Typically, the jaw carriers are moved towards each other by rotating the spindle. One jaw carrier is fixed, while the other is moved by actuating the drive spindle. Clamping jaws are attached to the jaw carriers as standard, enabling the clamping of a workpiece. After rotation of the drive spindle, the clamping jaws rest against the workpiece to be clamped. With further rotation of the drive spindle, a clamping force builds up between the clamping elements, which is transmitted to the workpiece via the clamping jaws. A specific torque applied to the spindle of the clamping drive by a turning tool corresponds to a specific clamping force between the clamping elements.Depending on the geometry of the clamping jaws, this clamping force of the clamping drive results in a more or less large clamping force acting on the workpiece.

[0004] Depending on the sensitivity of the workpiece being clamped, or the type of work to be performed on it, it is important to know the clamping force. Precise force adjustment is possible, for example, by tightening with a torque wrench. However, this only provides the user with information about the initial set force.

[0005] The invention is therefore based on the objective of providing a clamping drive and a method that makes it possible to monitor the force currently applied to the workpiece.

[0006] In the present invention, this problem is initially solved by the features of the characterizing part of claim 1 in that a force measuring module is connected to the drive spindle, that the force measuring module has at least one measuring element for detecting tensile and / or compressive deformations, that the force measuring module comprises an evaluation unit, and that signals from the measuring element can be received by the evaluation unit, wherein information regarding an applied force on the force measuring module can be determined by the evaluation unit as a function of the signal from the measuring element.

[0007] In one design, the drive spindle can be connected to the jaw carriers by means of clamping elements that can be attached to the opposite ends of the drive spindle. The clamping elements can be designed to fit positively into the respective jaw carriers. Due to the positive locking and the attachment of the clamping elements to the drive spindle, the drive spindle cannot be completely removed from the jaw carriers. Preferably, the clamping elements have a larger cross-section than the drive spindle or the extension element. The clamping elements can thus be inserted into a corresponding recess in the jaw carrier, with the recess simultaneously forming an opening for the passage of the drive spindle, the cross-section of which is smaller than the recess. Once the clamping element is inserted into the recess, the drive spindle cannot be moved further within the opening in the insertion direction.

[0008] The lower part could, for example, be a support rail. Using a support rail, the jaw carriers can be moved along the lower part in one direction without changing their orientation in other directions. However, other designs for the lower part are also conceivable, to which at least one jaw carrier can be attached.

[0009] The drive spindle can be driven or rotated by means of an additional tool or, for example, a crank attached to the drive spindle. The drive spindle can essentially be cylindrical in shape.

[0010] The evaluation unit can be an electrical device designed to acquire and process measurement signals from the measuring element. Electronic or electrical devices and / or other relevant devices or components according to the embodiments of the present invention described herein can be implemented using any suitable hardware, firmware (e.g., an application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of these devices can be housed on an integrated circuit (IC) or on separate IC chips. Furthermore, the various components of these devices can be implemented on a flexible printed circuit board, a tape carrier package (TCP), a printed circuit board (PCB), or on a single substrate.Furthermore, the various components of these devices can be a process or thread running on one or more processors in one or more computer devices, executing computer program instructions, and interacting with other system components to perform the various functions described here. The computer program instructions are stored in memory, which can be implemented in a computer device using standard memory, such as random access memory (RAM). The computer program instructions can also be stored on other non-transferable, computer-readable media, such as a flash drive or similar device.A competent person should also recognize that the functionality of different computer devices can be combined or integrated into a single computer device, or that the functionality of a particular computer device can be distributed among one or more other computer devices, without deviating from the scope of application of the exemplary embodiments of the present invention.

[0011] The electrical signals emitted by the measuring element are transmitted as a function of compression, stretching, or elongation of the material. In this way, the applied pressure, i.e., the applied tensile force, can be determined by the evaluation unit.

[0012] By implementing such a force measuring module, the clamping force applied to a workpiece can be continuously recorded. Most importantly, this allows for precise force adjustment when clamping a workpiece, thus preventing damage.

[0013] Further preferred embodiments of the invention result from the other features mentioned in the dependent claims.

[0014] In a first embodiment of the clamping drive according to the invention, the measuring element is arranged in a ring shape around the drive spindle. The measuring element can be arranged in a ring-shaped device that extends around the drive spindle as a force ring. In this way, the measuring element can be positioned in a space-saving manner in the area of ​​the drive spindle.

[0015] In a further preferred embodiment of the clamping drive according to the invention, the force measuring module includes a display device, and the information relating to an applied force can be displayed by the display device. The display device can comprise a display area that is arranged on the clamping drive in such a way that the user can read the force. The display area is preferably a display. However, it is also conceivable that it is a mechanical needle that moves proportionally to the applied force along a defined scale.

[0016] Furthermore, in a further embodiment of the invention, the force measuring module is connected to a power supply. In this way, for example, an electronic display can be powered.

[0017] In a further embodiment of the clamping drive according to the invention, the power supply can additionally include an energy storage device, in particular a chemical energy storage device. The energy storage device can preferably be in the form of a rechargeable battery. For this purpose, a charging contact socket can be provided on the clamping drive, which is electrically connected to the rechargeable battery, so that the battery can be recharged when a charging cable is inserted into the charging contact socket. In this way, the clamping drive can be positioned flexibly and does not need to be permanently connected to a power supply. It is also conceivable that the energy storage device is replaceable, so that a charging cycle in the clamping drive can be omitted. It is also conceivable that an inductive charging option is provided, so that the energy storage device can be charged wirelessly.The inductive charging option can be implemented according to a standard known from the state of the art.

[0018] To improve the functionality of the force module, a further embodiment of the clamping drive according to the invention provides that the evaluation unit includes a transmitter module, that the transmitter module includes a wireless communication interface, and that at least the information about the applied force can be transmitted via the wireless communication interface. The wireless communication interface can preferably be a WLAN connection or a Bluetooth connection. Measurement signals acquired by the force measuring module can be transmitted to a compatible receiver via the communication interface. In this way, information about the applied force on a workpiece, or about the course of the applied force over a defined period of time, can be transmitted, for example, to a central location. In a production environment, several clamping drives are often used.By transmitting the data to a central location, a user can monitor various clamping drives simultaneously and intervene if necessary, should the transmitted data indicate that a fault has occurred.

[0019] For good readability combined with a compact design, a further embodiment of the clamping drive according to the invention provides that the force measuring module is arranged within the first or second jaw carrier. Jaw carriers occupy the largest space in most commercial clamping drives. The height of the jaw carriers depends primarily on the spindle height and the height of the clamping jaws. This additional volume within the jaw carrier can be used to accommodate the force measuring module. Since the drive spindle engages with the jaw carrier anyway, the force measuring module can be installed in a space-saving manner, so that the dimensions of the clamping drive are not increased by the force measuring module.

[0020] Additionally or alternatively, a vibration sensor can be provided in a further embodiment of the invention, enabling the detection of vibrations of the clamping drive. The vibration sensor can also be connected to the force measuring module. In particular, the vibration sensor can be connected to the wireless communication interface in such a way that signals from the vibration sensor can be transmitted to a compatible receiver. By monitoring the vibrations, errors in the machining of the clamped workpiece, as well as in the machining tool, can be detected. Furthermore, measured vibrations can indicate that components are loosening or have already loosened. Preferably, the vibration sensor measures vibrations in the three-axis state.

[0021] The aforementioned problem is also solved by a method for operating a clamping drive according to the invention, wherein the evaluation unit provides a signal when a decrease or increase in an applied force is detected that is above or below a predetermined limit value. The above statements concerning the clamping drive according to the invention also apply accordingly to the method according to the invention.

[0022] Depending on the workpiece being clamped, it is important that the clamping force is not too high to avoid damaging the workpiece. Excessive force can also damage the drive spindle. Conversely, the force must not be too low to ensure the workpiece is securely held by the clamping mechanism. If the force increases or decreases during machining, this could indicate workpiece damage or a clamping error. Such an error can be signaled audibly or visually. The clamping mechanism may be equipped with signaling devices, such as an indicator light and / or a speaker. Alternatively, signaling could be provided via the wireless communication interface.A signal is then sent, for example, to an end device that the user of the clamping drive monitors.

[0023] In an initial embodiment of the method, an alarm is triggered when a sudden drop or increase in force is detected. Such a sudden increase or decrease in force most likely indicates damage or a malfunction during clamping or machining of the workpiece. Upon detection of this, a warning is issued, giving the user of the clamping drive the opportunity to react quickly and prevent further damage.

[0024] In a further embodiment, the evaluation unit can be configured to control the jaw carriers or the drive spindle. Upon detection of a force drop or increase, the evaluation unit can adjust the clamping drive so that a predefined force is applied to the workpiece. In the event of a sudden force increase or decrease, the evaluation unit can move the jaw carriers away from each other to release the workpiece, thus preventing further damage.

[0025] In a further embodiment of the method according to the invention, a vibration sensor is connected to the evaluation unit in such a way that vibrations of the clamping drive are detectable and a signal is generated when a vibration is detected that exceeds a predetermined limit. Vibrations can indicate that there is a defect in the workpiece or the tool. Such a defect can, for example, indicate damage that is not yet severe enough to cause the destruction of the workpiece and / or the tool.

[0026] Unless otherwise stated in individual cases, the various embodiments of the invention mentioned in this application can be advantageously combined with one another.

[0027] The invention is explained below using exemplary embodiments with reference to the accompanying drawings. These show: Figure 1 is a perspective view of an embodiment of a clamping drive with a force measuring module, Figure 2 is a sectional view of a drive spindle with a force measuring module according to the invention, Figure 3 is a representation of individual components of a force measuring module for a clamping drive and Figure 4 is a block view of a method for operating a clamping drive with a force measuring module.

[0028] Figure 1 Figure 1 shows a clamping drive 1 for a vise with a first jaw carrier 2 and a second jaw carrier 3. The first jaw carrier 2 and the second jaw carrier 3 are arranged on a base 4 and are movable relative to each other translationally by a drive spindle 5, which is Figure 1The first jaw carrier 2 and the second jaw carrier 3 are not connected to each other. The second jaw carrier 3 can be arranged on a first end face 6 of the drive spindle 5. The first jaw carrier 2 is arranged on a second end face 7 of the drive spindle 5. The second jaw carrier 3 is axially movable on the lower part 4, which is designed as a support rail. When the drive spindle 5 is actuated, the second jaw carrier 3 is moved so that the first jaw carrier 2 and the second jaw carrier 3 move relative to each other. Clamping jaws 8 are arranged on the jaw carriers 2 and 3. The clamping jaws 8 serve to clamp a workpiece (not shown) for further machining.

[0029] Furthermore, a force measuring module 9 is provided in the clamping drive 1. The force measuring module 9 is connected to the drive spindle 5. By implementing such a force measuring module 9, the clamping force applied to a workpiece (not shown here) can be continuously measured. In particular, an exact force can be set when clamping a workpiece, thus preventing damage to the workpiece.

[0030] In Figure 2The drive spindle 5 is shown in a cross-sectional view, on which the force measuring module 9 is simultaneously arranged. It can be seen that the force measuring module 9 has a measuring element 10 for detecting tensile and / or compressive deformations. Furthermore, an evaluation unit 11 is included, which can receive signals from the measuring element 10. The evaluation unit 11 can determine information regarding a force applied to the force measuring module 9 or the measuring element 10 as a function of the signal from the measuring element 10.

[0031] The measuring element 10 is arranged in a ring around the drive spindle 5. Furthermore, a display device 12 is provided, which has a display area 13 in the form of a screen. Information relating to an applied force is displayed in the screen area. In the present embodiment, this is done by displaying specific force values, which are transmitted to the display device 12 by the evaluation unit 11. A user can make settings via the display device 12 that also allow for other displays. In particular, it is conceivable that the evaluation unit can perform conversions that allow the applied force to be displayed in other units.

[0032] To supply power to the electronic component in the form of the force measuring module 9, the force measuring module is connected to a power supply in the form of a chemical energy storage device 14. The chemical energy storage device 14 is replaceably arranged in a housing 15 of the force measuring module 9. A cover (not shown) is provided on the housing 15 for replacing the energy storage device 14. This cover can be removed by the user and replaced after the energy storage device 14 has been replaced. It is possible that such a cover is provided only in the housing 15 of the force measuring module 9, in which case the force measuring module 9 must be removed to replace the energy storage device 14. However, it is also conceivable that a recess is provided in the second jaw carrier 3, into which the force measuring module 9 is inserted, through which the energy storage device 14 can be replaced without having to remove the force measuring module 9.

[0033] The force measuring module 9 also has a wireless communication interface 16. In this embodiment, the wireless communication interface 16 is implemented as a Bluetooth interface. Information about an applied force can be transmitted to compatible receivers via the wireless communication interface 16. These receivers can be end devices monitored by a user in a production facility where the clamping drive 1 is used. This makes it possible to transmit information about the applied force to a central location that can be more easily monitored by a user. The clamping drive 1 also includes a vibration sensor to detect vibrations at the clamping drive 1. This information can also be processed by the evaluation unit 11. Vibration detection can also be displayed in the display area 13 of the display device 12.Furthermore, this information can also be transmitted via the wireless communication interface 16 to an end device (not shown here) operated by a user.

[0034] Figure 3 Figure 1 shows various components of the force measuring module 9 without the housing 15. It illustrates that the measuring element 10 is arranged in a ring-shaped device 17, which extends as a force ring around the drive spindle 5. In this way, the measuring element 10 can be positioned in a space-saving manner in the area of ​​the drive spindle 5. The evaluation unit 11 is in the form of a circuit board 18 with at least one microchip 19.

[0035] Figure 4Figure 1 shows a block diagram of an embodiment of a method for operating a clamping drive 1 with a force measuring module 9. The force measuring module enables various scenarios that simplify the use of such a clamping drive 1 in a manufacturing process. In step 100, a workpiece is first clamped manually or automatically between the clamping jaws of the clamping drive 1. The force measuring module 9 determines the force applied to the workpiece.

[0036] If the evaluation unit 11 detects a decrease or increase in the applied force that exceeds or falls below a predefined limit, the detection is signaled in step 102. This can be done directly at the clamping drive 1 using loudspeakers or lamps, or via wireless transmission to a terminal device, which then sends a signal. Depending on the workpiece being clamped, it is important that the clamping force is not too high to avoid damaging the workpiece. Conversely, the force must not be too low to ensure that the workpiece is securely held by the clamping drive 1. If the force increases or decreases during the machining process, this could indicate workpiece damage or a faulty clamping operation.

[0037] In step 104, an alarm is triggered if a sudden drop or increase in force is detected by force measuring module 9. Such a sudden increase or decrease in force most likely indicates damage or a fault that occurred during clamping or machining of the workpiece. Upon such detection, a warning is issued, giving the user of the clamping drive the opportunity to react quickly to prevent further damage.

[0038] In addition, step 106 provides that the evaluation unit 11 can control the jaw carriers 2 and 3, or the drive spindle 5. Upon detection of a force drop or increase, the evaluation unit 11 can adjust the clamping drive 1 so that a predefined force is applied to the workpiece. In the event of a sudden force increase or decrease, the evaluation unit can move the jaw carriers 2 and 3 away from each other to release the workpiece, thus preventing further damage. Reference symbol list

[0039] 1 Clamping drive 2 First jaw carrier 3 Second jaw carrier 4 Lower part 5 Drive spindle 6 First end face 7 Second end face 8 Clamping jaws 9 Force measuring module 10 Measuring element 11 Evaluation unit 12 Display device 13 Display range 14 Energy storage 15 Housing 16 Wireless communication interface 17 Ring-shaped device 18 Circuit board 19 Microchip

Claims

1. Clamping drive (1) with a first jaw carrier (2) and a second jaw carrier (3), wherein the first jaw carrier (2) and the second jaw carrier (3) are connected to a drive spindle (5) in such a way that they can be moved translationally relative to each other by the drive spindle (5), wherein the first jaw carrier (2) is fixed to a lower part (4), characterized by that a force measuring module (9) is connected to the drive spindle (5), that the force measuring module (9) has at least one measuring element (10) for detecting tensile and / or compressive deformations, that the force measuring module (9) comprises an evaluation unit (11) and signals from the measuring element (10) can be received by the evaluation unit (11), whereby information regarding a force applied to the force measuring module (9) can be determined by the evaluation unit (11) depending on the signal from the measuring element (10).

2. Clamping drive (1) according to claim 1, characterized by the fact thatthe measuring element (10) is arranged in a ring shape around the drive spindle (5).

3. Clamping drive (1) according to claim 1 or 2, characterized by the fact that the force measuring module (9) includes a display device (12) and the information relating to an applied force can be displayed by the display device (12).

4. Clamping drive (1) according to one of claims 1 to 3, characterized by the fact that the force measuring module (9) is connected to a power supply.

5. Clamping drive (1) according to claim 4, characterized by the fact that the power supply includes an energy storage device (14), in particular a chemical energy storage device.

6. Clamping drive (1) according to one of claims 1 to 5, characterized by the fact that the evaluation unit (11) includes a transmitter module, the transmitter module includes a wireless communication interface (16) and at least the information about the applied force can be transmitted via the wireless communication interface (16).

7. Clamping drive (1) according to one of claims 1 to 6, characterized by the fact that the force measuring module (9) is arranged within the first jaw carrier (2) or the second jaw carrier (3).

8. Clamping drive (1) according to one of claims 1 to 7, characterized by the fact that a vibration sensor is provided by which vibrations of the clamping drive (1) can be detected.

9. Method for operating a clamping drive (1) according to any one of claims 1 to 8, characterized by the fact that The evaluation unit (11) signals when a decrease or increase in an applied force is detected that is above or below a specified limit value.

10. Method according to claim 9, characterized by the fact that An alarm is triggered if a sudden drop or increase in power is detected.

11. Method according to claim 9 or 10, characterized by the fact thata vibration sensor is connected to the evaluation unit in such a way that vibrations of the clamping drive can be detected and that a signal is given when a vibration is detected that exceeds a predefined limit value.

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