Workpiece clamping device

Abstract

Workpiece clamping device (9) for a workpiece clamping system (1) for machining operations, wherein the workpiece clamping system comprises a workpiece clamping device (9) configured to be connected to a drive unit (10) to provide a drive fluid that drives the workpiece clamping device (9), wherein the workpiece clamping device (9) comprises: - a basic body (2); - a pair of clamping jaws (4) which are movably attached to the base body; - a holding and release system (60) for selectively holding the clamping jaws on the base body and for releasing the clamping jaws from the base body; and - a workpiece presence detection system (40) configured to detect the presence of a workpiece between the clamping jaws.

Description

AREA

[0001] The present disclosure relates to a workpiece clamping device, for example a vise, for use in a workpiece clamping system for machining operations. The disclosure also relates to the workpiece clamping system. BACKGROUND

[0002] Pneumatic vises are well-known in engineering. They are used to clamp workpieces quickly and with repeatable accuracy. Existing solutions typically use conventional interchangeable jaws or complex pressure systems with pins for adaptive clamping. These established systems are often bulky, difficult to automate, and offer limited flexibility in handling different types of workpieces.

[0003] Pneumatic vises have several disadvantages: • lack of speed and ease in changing the jaws; • no possibility to combine different jaw concepts (soft and ground jaws) within the same system; • No integrated and reliable workpiece detection without external sensors; • Limited suitability for robot handling in automated production lines. SUMMARY

[0004] According to one aspect, a workpiece clamping device is provided for a workpiece clamping system for machine operations, wherein the workpiece clamping system comprises a workpiece clamping device configured to be connected to a drive unit to provide a drive fluid that drives the workpiece clamping device, wherein the workpiece clamping device comprises: - a basic body; - a pair of clamping jaws that are movably attached to the base body; - a holding and release system for selectively holding the clamping jaws on the base body and for releasing the clamping jaws from the base body; and - a workpiece presence detection system configured to detect the presence of a workpiece between the clamping jaws.

[0005] In embodiments of the present invention, the drive unit is a pneumatic or hydraulic drive unit.

[0006] In embodiments of the present invention, the workpiece clamping device is configured such that it causes the clamping jaws to move at least synchronously and / or symmetrically in order to form a centric clamping device, for example a centric vise.

[0007] In embodiments of the present invention, the holding and release system is configured to detach a clamping jaw from the base body, optionally without the use of mechanical fasteners.

[0008] In embodiments of the present invention, the holding and releasing system is configured to fasten or release the clamping jaws using a quick-change mechanism.

[0009] In embodiments of the present invention, the workpiece presence detection system (40) comprises: - an air channel in the clamping jaw with at least one channel opening positioned in a contact area where the clamping unit comes into contact with a workpiece when one is present, preferably with an air channel in the base body; and - a sensor configured to detect fluctuations in air pressure in the air channels, the sensor optionally being configured to generate a sensor signal indicating the presence of a workpiece positioned on the associated clamping jaw.

[0010] In embodiments of the present invention, the holding and release system comprises a wedge-hook connection which positions the clamping jaws in the base body with high repeatability and stability.

[0011] In embodiments of the present invention, the clamping jaws are soft, machinable clamping jaws, for example made of aluminum.

[0012] In embodiments of the present invention, the clamping jaws are configured to be provided with ground jaws, wherein the ground jaws are at least partially made of steel and / or are provided with adjustable steel inserts.

[0013] In embodiments of the present invention, the base body is lightweight, preferably made of aluminum, so that the unit can be handled by lightweight robots or robots.

[0014] In embodiments of the present invention, the clamping unit is configured to be suitable for both external and internal clamping of a workpiece.

[0015] According to embodiments of the present invention, a pneumatically actuated, centric vise is equipped with quickly interchangeable clamping jaws. The jaws are detachably connected to the base body by means of a quick-change mechanism with a wedge hook connection, thus ensuring high repeatability and stability. The jaws are provided with internal air channels that enable the detection of a workpiece's presence, even when using soft, machinable jaws. In addition to the soft jaws, the system also includes ground jaws with adjustable steel inserts, offering high flexibility in use. The base body is lightweight, preferably made of aluminum, so that the vise can be changed by lightweight robots or robotic operators.The vise is suitable for both external and internal clamping of workpieces, thus enabling fast, precise and automated production in small and medium series. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] This and other aspects of the present invention will now be described in more detail with reference to the accompanying drawings, which currently show preferred embodiments. The same numbers refer to the same features in all drawings. Fig. Figure 1 is a side view of an embodiment of a workpiece clamping system consisting of a workpiece clamping device 9 and a pneumatic or hydraulic drive unit 10; Fig. Figure 2A is a two-dimensional cross-sectional view through one of the movable jaws 5, 6 of the embodiment of the workpiece clamping device. Fig. 1; Fig. is a 3D cross-sectional view according to the embodiment of the figures and 2A; Fig. Figure 3 is a longitudinal section of the workpiece clamping device made of Fig. 1; Fig. Figure 4 is a side view of an embodiment of a workpiece clamping device which is provided with two jaws made of hardened steel; The Fig. 5A-5E are longitudinal sections according to Fig. 3, which show the release of a jaw from the base body 2 of a workpiece clamping device at various stages, wherein Fig. 5A shows a first stage in which the jaw is fully attached, Fig. 5E shows a fifth stage in which the cheek is completely detached, and the Fig. Show intermediate stages 5B-5D.

[0017] Embodiments of the present disclosure relate to a pneumatically actuated centering clamping vise with quickly interchangeable clamping jaws, which has at least one of the following advantageous features: 1. Quick-change mechanism with wedge-hook connection: The jaws are detachably connected to the base body and are positioned with high repeatability via a wedge-hook connection. 2. Airflow detection in the jaws: The jaws are equipped with internal air channels that make it possible to detect the presence of a workpiece based on pressure fluctuations. 3. Modular jaw concept: Both soft, machined jaws and ground jaws with adjustable steel inserts can be used within the same system. 4. Lightweight aluminum body: The base body is preferably made of aluminum, making the vise suitable for handling by robots.

[0018] In a preferred embodiment, the workpiece clamping device is a central vise comprising a pneumatically driven base body in which two clamping jaws move symmetrically towards each other under the influence of a pneumatic cylinder. The jaws are provided with a wedge-hook profile that corresponds to a mating profile in the base body, thus ensuring precise and stable positioning. The soft jaws are made of aluminum and can be machined according to the contour of specific workpieces. For rough machining, ground jaws with adjustable steel inserts can be mounted. In both embodiments, internal air channels are provided that are connected to an external compressed air source and a pressure sensor, allowing the presence and proper clamping of a workpiece to be verified.The lightweight base allows for quick replacement of the vise using standard robot grippers, making the system ideal for automated production environments.

[0019] Fig. Figure 1 shows a workpiece clamping system 1, which is intended in particular for use in machining operations, for example, milling, scraping, or drilling a (metal) workpiece. The workpiece clamping system 1 comprises a workpiece clamping unit 9 and a hydraulic or pneumatic drive unit 10. The workpiece clamping unit 9 comprises a base body 2 and a pair of clamping jaws 5, 6, which are movably attached to the base body 2. The base body 2 is in fluid communication (via a closing fluid connection 3 configured for closing the clamping jaws and an opening fluid connection 5 configured for opening the clamping jaws) with a fluid (liquid or gas, for example, air, from the hydraulic or pneumatic drive unit 10, as will be explained later) with the workpiece clamping unit 9 (hereinafter also simply referred to as the "vise").The workpiece clamping device 9 comprises a base body 2 shaped to be stably positioned on a floor, table, or the like. Two movable jaws 5, 6 are connected to the top of the base body 2. Each jaw 5, 6 is movable in the longitudinal direction (see arrows 7). The workpiece clamping device 9 can be configured so that the jaws move synchronously and / or symmetrically towards each other (to clamp a workpiece, not shown) or away from each other (to release the workpiece). Fig. The jaws 5 and 6 are in an open position, while Fig. the jaws 5, 6 are in a closed position. Preferably, the workpiece clamping device is a centric clamping device (i.e., a centric vise) in which the workpiece is clamped along an imaginary centerline of the base body 2 (which extends in the transverse direction 11 ( Fig. )) is clamped.

[0020] The jaws 5, 6 are generally identical and function in the same way. The jaws 5, 6 are preferably soft jaws made of aluminum or a similar material and can be machined to conform to the contour of the workpiece to be clamped. Each jaw 5 is provided on its underside with an elongated guide element 13 extending longitudinally and having a substantially T-shape in cross-section with two opposing radial flanges 10. The elongated guide element 13 can be received in a correspondingly shaped elongated longitudinal recess 25 provided in the top of the base body 2. The opposing radial flanges 10 of the elongated guide element 13 can slide in corresponding radial recess portions 26 of the recess 25 to move the associated jaw 5, 6 in the longitudinal direction 7.This design ensures precise and stable positioning of both jaws 5, 6 relative to the base body 2.

[0021] With reference to the Fig. 3, Fig. 5A and Fig. Section 5B describes in more detail the mechanism for opening and closing the jaws. Fig. Figure 3 shows a central piston 18 arranged to be movable axially (i.e., upwards and downwards) within a cylinder 16 provided in the base body 2. The cylinder 16 comprises a pneumatic fluid chamber 21, which is divided by a radial piston section 55 of the piston 18 into an upper fluid chamber section 22 and a lower fluid chamber section 23. The upper fluid chamber section 22 is in fluid communication (via a fluid channel not shown in the figures) with the aforementioned fluid connection 3, which in turn is connected to the drive unit. When the pressure of the hydraulic or pneumatic fluid from the fluid connections 3 is increased, the fluid in the upper fluid chamber section 22 pushes the piston 18 downwards (from the position shown in Figure 3). Fig. shown position in the Fig. (position shown). Similarly, the liquid in the lower liquid chamber part 23 pushes the piston 18 upwards (from the position shown). Fig. shown position in the Fig. (position shown), when the pressure of the hydraulic or pneumatic fluid in fluid connection 4 is increased.

[0022] The upper end 70 of the piston 18 is generally T-shaped and has two transversely extending flanges. Each flange is provided with an inclined slot 32 (which is open at its lower end) in which a transversely extending drive pin 30 can be slidably received. The inclined slot 32 defines an inclined engagement surface 35 which is in contact with an associated drive pin 30, such that when the piston 18 moves from the position in Fig. upwards into the position in Fig. When the piston 18 is moved, the jaws move apart and form a gap (G) to receive the workpiece, while the jaws 5, 6 move towards each other to clamp the workpiece when the piston 18 moves from the position in Fig. downwards into the position in Fig. is being moved.

[0023] The way in which the jaws 5, 6 are attached to the base body 2 also allows for a quick-change mechanism (referred to here as the holding and release system 60), which makes it possible to easily remove and / or replace each of the jaws. In the Fig. In the open position shown, a jaw 5, 6 is prevented from moving further in the opening direction by the presence of a holding and release system 60. The holding and release system 60 comprises a spring-loaded retaining element 62, for example a ball, which is arranged in a recess in the upper part of the base body 2, the spring 61 being configured to push the retaining element 62 upwards. The retaining element 62 contacts an inclined first engagement surface 65 on the bottom 50 of the jaw 5, 6. The retaining elements 62s hold the respective jaws 5, 6 firmly in their upper position, thus preventing the jaws from being accidentally removed from the base body 2. However, if the piston 18 is moved upwards to such an extent that the drive pins 30 are located below the respective inclined slots 32, and if a suitable manual force is applied by an operator (i.e.,a suitable force in the longitudinal direction 7), causes the jaws 5, 6 to move the retaining element 62 downwards against the action of the spring, so that the jaws can be moved further (see . Fig. 5C and Fig. 5D), until they are completely removed from the base body 2 (see Fig. 5E). A new jaw 5, 6 can be easily fitted by moving the new jaw in the opposite direction (starting from the position in Fig. , then 5D, 5C, 5B and 5A). For this purpose, the underside 50 of each jaw 5, 6 is provided with an inclined second engagement surface 66, which is positioned opposite the first engagement surface 6). The holding and releasing system 60 makes it possible to easily and yet securely attach jaws to a base body 2 and / or detach them from the base body 2 without the need for additional mechanical fasteners such as screws. Furthermore, the accuracy of the jaw attachment remains high even with repeated jaw replacements (high repeatability).

[0024] The workpiece clamping device 9 of the workpiece clamping system 1 can include a workpiece presence detection system 40. The workpiece presence detection system 40 is configured to automatically detect the presence of a workpiece between the jaws 5, 6. The workpiece presence detection system 40 consists of a number of air channels arranged internally in at least one of the jaws 5, 6 and in the base body 2.

[0025] An example of a workpiece presence detection system 40 is in the Fig. (The figure shows only a part of the workpiece presence detection system 40; air channels 43 and 44 are missing. Typically, the workpiece clamping device 9 is manufactured and sold without channels 43 and 44. Channels 43 / 44 are added by the end user, for example, by drilling two holes in jaws 5 and 6, so that the exact position of the channels can be determined by the actual shape of the workpiece to be handled by the end user.) Air channel 43 (and air channels 43 and 44) ​​in jaws 5 and 6 are connected to an air channel 41 in the base body 2. To ensure a proper connection between channels 41 and 42 regardless of the jaw position (the closed position of the jaws), Fig. 5A, the closed position of Fig.To ensure the presence of the workpiece between jaws 5 and 6 (5B or any intermediate position), an elongated air chamber 45, open at its top (and / or an elongated air chamber on the underside 50 of the jaw), is provided on the upper side of the base body 2. The inner channels 41 are connected to a pressure sensor (not shown) configured to measure fluctuations in air pressure in the channels 41, 42, 43, 44 of the workpiece presence detection system 40. These fluctuations are representative of the presence of the workpiece between jaws 5 and 6.

[0026] The principles of the invention have been set out above in conjunction with specific embodiments; however, it is understood that this description serves only as an example and does not represent a limitation of the scope of protection as determined by the attached claims.

Claims

[1] Workpiece clamping device (9) for a workpiece clamping system (1) for machining operations, wherein the workpiece clamping system comprises a workpiece clamping device (9) configured to be connected to a drive unit (10) to provide a drive fluid that drives the workpiece clamping device (9), wherein the workpiece clamping device (9) comprises: - a basic body (2); - a pair of clamping jaws (4) which are movably attached to the base body; - a holding and release system (60) for selectively holding the clamping jaws on the base body and for releasing the clamping jaws from the base body; and - a workpiece presence detection system (40) configured to detect the presence of a workpiece between the clamping jaws. [2] Workpiece clamping device (9) according to claim 1, wherein the drive unit (10) is a pneumatic or hydraulic drive unit. [3] Workpiece clamping device (9) according to claim 1 or 2, which is configured to cause the clamping jaws to move at least synchronously and / or symmetrically in order to form a centric clamping device, for example a centric vise. [4] Workpiece clamping device (9) according to one of the preceding claims, wherein the holding and release system (60) is configured to detach a clamping jaw from the base body, optionally without the use of mechanical fastening means. [5] Workpiece clamping unit (9) according to one of the preceding claims, wherein the holding and releasing system (60) is configured to fasten or release the clamping jaws using a quick-change mechanism. [6] Workpiece clamping device (9) according to one of the preceding claims, wherein the workpiece presence detection system (40) comprises: - an air channel in the clamping jaw with at least one channel opening positioned in a contact area where the clamping unit comes into contact with a workpiece when a workpiece is present, preferably with an air channel in the base body (2); and - a sensor configured to detect fluctuations in air pressure in the air ducts, the sensor optionally being configured to generate a sensor signal indicating the presence of a workpiece positioned against the associated clamping jaw. [7] Workpiece clamping unit (9) according to one of the preceding claims, wherein the holding and release system (60) comprises a wedge-hook connection which positions the clamping jaws in the base body with high repeatability and stability. [8] Workpiece clamping device (9) according to one of the preceding claims, wherein the clamping jaws are soft, machinable clamping jaws, for example made of aluminium. [9] Workpiece clamping device (9) according to one of the preceding claims, wherein the clamping jaws are designed such that they are provided with ground jaws, wherein the ground jaws are at least partially made of steel and / or are provided with adjustable steel inserts. [10] Workpiece clamping device (9) according to one of the preceding claims, wherein the base body is lightweight, preferably made of aluminium, so that the device can be handled by robots. [11] Workpiece clamping device (9) according to one of the preceding claims, wherein the clamping device is configured to be suitable for both external and internal clamping of a workpiece. [12] Workpiece clamping device (1) for machining, comprising a workpiece clamping device (9) and a drive unit (10) for driving the workpiece clamping device (9).

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