Gripping device and safety clamping system for securing components

Abstract

Gripping device (10), comprising a compressed air cylinder (30) with a compressed air chamber (31) which can be supplied with compressed air (p) via a compressed air line (40), comprising a piston (50) arranged in the compressed air chamber (31), wherein the piston (50) can be linearly deflected against a return spring (60) by supplying the compressed air chamber (31) with compressed air (p), and the piston (50) is connected to a piston rod (51), characterized in that the piston rod (51), which can be linearly deflected by the piston (50), is connected via a deflection lever (52) to at least one gripper arm (20) and / or to a locking mechanism (80) for actuating at least one externally driven gripper arm (21), wherein the externally driven gripper arm (21) is locked in an open position (I) by the non-actuated locking mechanism (80).

Description

[0001] The invention relates to a gripping device comprising a pneumatic cylinder with a compressed air chamber, which can be supplied with compressed air via a compressed air line, and a piston arranged in the compressed air chamber. Furthermore, the invention relates to a clamping system.

[0002] Production plants use various transport and handling systems to pick up, transport, and process parts and components. For example, pneumatic grippers or suction grippers can be used to hold a component. The pneumatic grippers can clamp the component using compressed air. While compressed air is being supplied, the pneumatic grippers remain closed.

[0003] Similarly, suction cups can be applied to the surface of the component and hold the component using a vacuum. A vacuum chamber is formed between a surface of the component and the suction cup, which holds the component with a defined load-bearing capacity. The load-bearing capacity of the suction cup is directly dependent on the vacuum supply.

[0004] A disruption in the compressed air supply or a vacuum supply can cause the aforementioned solutions for picking up components to lose their load-bearing capacity, causing the component to fall. A falling component can cause not only personal injury but also property damage. For this reason, safety clamps are used to secure the component in addition to pneumatic grippers or suction grippers. For this purpose, the component is enclosed from below by the gripping devices of the safety clamp.

[0005] In the event of a defect in the compressed air or vacuum supply, clamps can catch the component and prevent damage. For example, compressed air-operated clamps are well known. However, these clamps increase compressed air consumption.

[0006] Magnetic clamps are also known, which can secure the component using electrically switchable magnetic fields. However, such electromagnetic clamps have limited applications and cannot be used, for example, with components made of plastic or aluminum.

[0007] JP H05-285 876 ​​A discloses a gripping device that secures a plate-shaped workpiece against falling. The gripping device is operated with compressed air and can be mounted on a robot arm. Guide elements are provided to prevent lateral or horizontal slipping of the workpiece. The gripping device has a fall-prevention mechanism in which a compressed air cylinder with a plunger can press against a lever and deflect the lever along a rotational axis. The lever is L-shaped and can secure the workpiece at the bottom if necessary. The lever is moved into a closed position by the plunger, counteracting a spring. Without the action of the plunger, the spring moves the lever into an open position of the gripping device. DD 2 90 382 A5 describes a two-finger gripper for the automatic handling of small parts. A handling device with a gripping device is known from DE 29 37 061 C2.

[0008] The invention is based on the object of creating a gripping device, particularly for safety clamping systems, which can secure a component without time restrictions even in the event of a compressed air failure. This object is achieved by the features specified in claim 1. Further advantageous embodiments of the invention are described in the subclaims.

[0009] According to one aspect of the invention, a gripping device, in particular for a safety clamp, is provided. The gripping device comprises a pneumatic cylinder with a compressed air chamber, which can be supplied with compressed air via a compressed air line. Furthermore, the gripping device comprises a piston arranged in the compressed air chamber, wherein the piston can be linearly deflected against a return spring by applying compressed air to the compressed air chamber. The return spring can be arranged inside the compressed air chamber or outside the compressed air chamber. The piston is connected to a piston rod.

[0010] The compressed air serves as the energy source or counterforce for compressing or expanding the return spring. If the compressed air supply fails or is shut off, the counterforce is no longer provided, allowing the return spring to move the piston and piston rod to their initial position.

[0011] According to an alternative or additional embodiment, the piston rod can be deflected against the return spring based on other energy sources. For example, the piston rod can be deflected or tensioned against the force of the return spring by an electromagnet or a hydraulic fluid.

[0012] According to the invention, the piston rod, which can be deflected linearly by the piston and / or an electromagnet, is connected via a reversing lever to at least one gripper arm and / or to a locking mechanism for actuating at least one externally driven gripper arm.

[0013] The at least one gripper arm can thus be held in an open position as long as the energy source is available and the piston rod is deflected linearly against the return spring. After the energy source or power supply is shut off, the at least one gripper arm closes automatically. This measure can provide a fail-safe mechanism that can reliably support a picked-up component.

[0014] Preferably, the at least one gripper arm can be arranged relative to the component in a closed position such that the return spring is not stretched by the weight of the component. For this purpose, the piston rod can decouple the gripper arm from the return spring via a tilting mechanism, whereby the weight of the component is essentially applied to a joint of the gripper arm.

[0015] In an alternative or additional embodiment, the piston, deflected against the return spring, can function with the piston rod as a locking mechanism that can lock or release a drive mechanism of the gripper arm. For this purpose, the externally driven gripper arm can be held in the open position against a drive spring force and locked by the piston rod. The piston rod is also positioned in an open position deflected against the return spring. If the energy source, such as the compressed air supply, fails, the piston rod is moved back to its initial position by the return spring. During the movement initiated by the return spring, the locking mechanism is opened and the gripper arm or a drive of the gripper arm is unlocked.Through such an unlocking, a drive spring or an alternative drive force can act on at least one gripper arm, thus placing the gripper arm in a closed state. Such a locking mechanism can provide fail-safe protection against a falling component and be technically simple.

[0016] According to one embodiment, by applying compressed air to the compressed air chamber, the at least one gripper arm can be moved into an open position via the piston rod and / or the locking mechanism can be locked in a locked state. The piston rod can thus be connected to the at least one gripper arm directly or via a mechanical connection. Preferably, the gripper arm can be deflected, moved, or rotated by the piston rod. Analogous to the direct drive of the gripper arm via the piston rod, the piston rod can interact with the locking mechanism and thus initiate or prevent a movement of the gripper arm. Through these measures, the gripper arm can be opened when the energy source for deflecting the piston rod against the return spring is available. In the event of a failure of the energy source, unintentional opening of the at least one gripper arm is not possible.For this purpose, an emergency release of the gripper arm can be provided.

[0017] A robust and efficient fail-safe device for a clamping system can be provided if, in the event of a pressure drop in the compressed air chamber, at least one gripper arm can be moved into a closed position via the return spring and / or the locking mechanism can be unlocked. The falling pressure can thus be detected and serve as a decreasing energy source to release the return spring. This eliminates the need for separate sensors and evaluation electronics to detect a pressure drop, making the gripping device particularly cost-effective.

[0018] The externally driven gripper arm can be driven, for example, by a spring, such as a torsion spring, leg spring, coil spring, and the like. In an open position of the gripper arm, the drive spring is tensioned, and the gripper arm is locked against closing or movement by the locking mechanism. This allows for the provision of continuous drive energy for the at least one gripper arm, which can be released as needed or in the event of a pressure drop to move the gripper arm into a closed position.

[0019] According to a further embodiment, the energy source can be unlocked by the unlocked locking mechanism of the externally driven gripper arm to assume a closed position.

[0020] The at least one gripper arm can be moved particularly efficiently from an open position to a closed position if the externally driven gripper arm can be moved into a closed position by a spring element acting directly or indirectly on the externally driven gripper arm. In particular, the at least one externally driven gripper arm can be moved directly by the drive spring or via a coupling mechanism. For example, a lever or a lever connection to the externally driven gripper arm can be used to be driven by the drive spring.

[0021] According to a further embodiment, the locking mechanism connected to the piston rod is configured to unlock a spring-loaded coupling mechanism of the externally driven gripper arm or an externally driven gripper arm in the event of a pressure drop. This allows the piston rod to directly block or release a coupling mechanism or the externally driven gripper arm. For example, the piston rod can protrude into a section of the gripper arm or the coupling mechanism in a form-fitting manner, thus inhibiting a movement of the gripper arm initiated by the drive spring.

[0022] The piston rod can release the externally driven gripper arm particularly easily if the locking mechanism has a pawl that engages with a corresponding locking section for locking the externally driven gripper arm in an open position. The pawl can, for example, be attached to an end of the piston rod opposite the piston or can be connected to the end. A pressure drop or energy loss can cause the return spring to move the piston rod to the initial position, which separates or retracts the pawl from the locking section.

[0023] According to a further embodiment, the locking section is arranged on the externally driven gripper arm or on the coupling mechanism. This allows for direct interaction between the pawl attached to the piston rod and the locking section. In particular, the locking section and the pawl can interlock when the externally driven gripper arm is in an open position. Thus, the locking mechanism can be formed by the locking section and the pawl. Preferably, the pawl can be pulled out of the locking mechanism with minimal force in order to unlock the externally driven gripper arm and move it into a closed position.

[0024] A manual or automated gripper arm change can be carried out particularly safely if at least one gripper arm and / or the locking mechanism can be locked in the open or closed position of the gripping device. Such locking of the gripping device can also be advantageous in docking processes with regard to operational safety. The gripping device can be locked, for example, using a locking lever or a locking pin.

[0025] According to a further aspect of the invention, a safety clamping system for securing a component is provided. The safety clamping system comprises at least two gripping devices according to the invention, which can be placed beneath a component for securing purposes.

[0026] The safety clamping system can preferably be connected to a power source, such as pneumatic, electrical, or hydraulic, which holds the gripping devices in an open position. The gripping devices can be designed to minimize energy consumption. If the power source fails, for example, due to a drop in compressed air, the gripping devices are automatically closed by the integrated return springs or drive springs. This provides a technically simple and robust fail-safe mechanism.

[0027] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. They show: Fig. 1 schematic side view of a safety clamping system in a production plant with a component to be secured, Fig. 2A, Fig. 2B schematic sectional views of a gripping device according to the invention according to an embodiment, Fig. 3A, Fig. 3B schematic sectional views of a gripping device according to the invention with an externally driven gripper arm according to an embodiment, and Fig. 4A, Fig. 4B schematic sectional views of a gripping device according to the invention with an externally driven gripper arm according to a further embodiment.

[0028] In the figures, the same structural elements have the same reference numerals.

[0029] The Fig. 1 shows a schematic side view of a safety clamping system 100 in a production plant 110 with a component 120 to be secured. A section of the production plant 110 is shown, in which a gripping device 10 of the safety clamping system 100 is illustrated in detail.

[0030] The gripping device 10 is attached to a support plate 101 of the safety clamping system 100 and serves to secure the component 120 against accidental falling. The gripping device 10 has a gripper arm 20, which is shown by way of example in an open position I and a closed position II.

[0031] In the open position I of the gripper arm 20, the component 120 can be removed from the production system 110 or inserted into the production system 110. In the closed position II, the gripper arm 20 grips the underside of the component 120 without touching the component 120. As a result, the gripper arm 20 forms a catch base for the component 120. The catch clamping system 100 can have several gripping devices 10, which can secure the component 120 in different positions.

[0032] The gripping device 10 is shown in the figures as being operable by compressed air. Alternatively, the gripping device 10 can also be operated by electrical energy, electromagnets, or hydraulics.

[0033] The gripping device 10 has a compressed air cylinder 30 which is designed to receive the provided compressed air and thus deflect the gripper arm 20.

[0034] In the Fig. 2A and Fig. 2B are schematic sectional views of a gripping device 10 according to the invention according to an embodiment. In particular, Figs. 2A and 2B show the Fig. 1 shows the gripping device 10 of the gripping device 10 illustrated here with regard to its mode of operation.

[0035] The Fig. 2A shows the gripping device 10 in a closed position II of the gripper arm 20. In the Fig. 2B, the gripping device 10 is shown in an open position I of the gripper arm 20.

[0036] The gripping device 10 has a compressed air cylinder 30 with a compressed air chamber 31. A compressed air line 40 opens into the compressed air chamber 31. The compressed air line 40 serves to provide energy in the form of compressed air p.

[0037] A piston 50 is arranged in the compressed air chamber 31 and is connected to a piston rod 51 at one end. The piston 50 can be arranged in the compressed air chamber 31 in a substantially airtight manner and can be displaced in the compressed air chamber 31 in the linear direction x.

[0038] Furthermore, a return spring 60 is arranged in the compressed air chamber 31 between an end section 32 of the compressed air cylinder 30 and the piston 50. When compressed air p is introduced into the compressed air chamber 31, the piston 50 is deflected toward the end section 32 of the compressed air cylinder 30 and the return spring 60 is compressed. In the compressed state of the return spring 60, the gripper arm 20 is in the open position I, which is maintained with the existing compressed air supply p.

[0039] The piston rod 51 projects linearly from the compressed air chamber 31 into a housing 11 of the gripping device 10. In the housing 11, the piston rod 51 is connected to the gripper arm 20 via a reversing lever 52. The reversing lever 52 is rotatably connected at its end to the piston rod 51 and the gripper arm 20. The gripper arm 20 is rotatably arranged on a fixed axis of rotation R. The reversing lever 52 is connected to the gripper arm 20 offset by an offset V to the axis of rotation R. Through such a mechanical coupling, a linear movement of the piston rod 51, which is driven by the piston 50, can be converted into a rotary movement of the gripper arm 20 about the axis of rotation R.

[0040] If the compressed air supply p is interrupted, the return spring 60 is no longer compressed and can push the piston 50 away from the end section 32, whereby the piston rod 51 is pushed out of the compressed air chamber 31 and the gripper arm 20 is rotated under the component 120.

[0041] The gripper arm 20 is arranged relative to the piston rod 51 and the return spring 60 such that, in the closed position II, a weight force G generated by the component 120 is decoupled from the return spring 60. In the illustrated embodiment, the weight force G acts exclusively on the rotational axis R of the gripper arm 20. As a result, the return spring 60 does not have to be able to support the component 20 itself and can be dimensioned accordingly weaker to enable minimal compressed air consumption.

[0042] The Fig. 3A and the Fig. 3B show schematic sectional views of a gripping device 10 according to the invention with an externally driven gripper arm 21 according to an embodiment. Fig. 3A, the gripping device 10 is in an open position I and in the Fig. 3B in a closed position II of the externally driven gripper arm 21.

[0043] The externally driven gripper arm 21 cannot be directly deflected into the closed position II by the return spring 60. A drive spring 70 is arranged at the pivot point R of the externally driven gripper arm 21, which is tensioned in the open position I of the externally driven gripper arm 21. In the illustrated embodiment, the drive spring 70 is designed as a leg spring.

[0044] The gripping device 10 has a locking mechanism 80, which can be actuated by driving the piston 50 and the piston rod 51. The locking mechanism 80 has a pawl 81 and a locking portion 82. The pawl 81 is connected to the end of the piston rod 51. The locking portion 82 is arranged on the externally driven gripper arm 21. The interaction of the pawl 81 with the locking portion 82 prevents the drive spring 70 from being released. The externally driven gripper arm 21 thus remains in its open position I.

[0045] The pawl 81 blocks the locking section 82 while the compressed air chamber 31 is supplied with compressed air p and the return spring 60 is compressed. In contrast to the Fig. In the embodiment shown in Figure 2, the return spring 60 is positioned at an end 33 opposite the end portion 32. Thus, the piston rod 51 is pushed out of the compressed air chamber 31 when the return spring 60 is compressed, and is drawn into the compressed air chamber 31 when the return spring 60 is expanded.

[0046] For example, a pressure of 6 bar may be sufficient to compress the return spring 60 and hold it in the compressed state. If the compressed air supply is interrupted, the return spring 60 expands again. The return spring 60 then pushes the piston 50 and thus also the piston rod 51 toward the end section 32. Due to the direct connection of the piston rod 51 and the locking pawl 81, the locking pawl 81 is pulled away from the locking section 82, and the locking mechanism 80 is unlocked.

[0047] After unlocking the locking mechanism 80, the drive spring 70 can act unhindered on the externally driven gripper arm 21 and move it into the closed position II. The corresponding movement is illustrated by an arrow 71.

[0048] In the Fig. 4A and the Fig. 4B are schematic sectional views of a gripping device 10 according to the invention with an externally driven gripper arm 21 according to a further embodiment. In contrast to the Fig. In the embodiment shown in Figure 3, the drive spring 70 does not act directly on the externally driven gripper arm 21, but rather on a coupling mechanism 90 of the externally driven gripper arm 21. The externally driven gripper arm 21 is designed, for example, as a catch hook and can perform a multi-stage rotary movement 71 via the coupling mechanism 90. The rotary movement 71 allows the externally driven gripper arm 21 to pivot beneath the component 120.

[0049] The coupling mechanism 90 has two fixed pivot points R1, R2. A first rod 91 is rotatably attached to a first pivot point R1. A spring-loaded drive rod 92 is attached to the second pivot point R2. The drive spring 70 thus acts on the drive rod 92. The drive rod 92 is also rotatably connected to a gripper rod 93 at an end opposite the second pivot point R2. The gripper rod 93 merges into the externally controlled gripper arm 21 on one side or is connected to the externally controlled gripper arm 21. At an end opposite the gripper arm 21, the gripper rod 93 is rotatably connected to the first rod 91. The locking section 82, which interacts with the pawl 81, is attached to a connection point between the gripper rod 93 and the first rod 91.

[0050] The pivot points R1, R2 are offset from one another. If the pawl 81 is removed from the locking mechanism 80, the first rod 91 can swing freely, allowing the spring force of the drive spring 70 to also act on the drive rod 92. This allows the gripper rod 93 to pivot around the component 120 and, in a second step, hook under the component 120. The corresponding direction of action, or the rotational movement initiated by the drive spring 70, is illustrated by arrow 71. List of reference symbols 100 safety clamping system 101 Carrier plate of the safety clamping system 110 production plant 120 components 10 Gripping device 11 Housing of the gripping device 20 pneumatically driven gripper arm 21 externally driven gripper arm 30 pneumatic cylinders 31 Compressed air chamber 32 End section of the compressed air chamber 33 end of the compressed air chamber opposite the end section 40 compressed air line 50 pistons 51 Piston rod 52 bell crank 60 return spring 70 Mainspring 71 Drive direction of the drive spring 80 locking mechanism 81 pawl 82 locking section 90 Coupling mechanism 91 first bar 92 Drive rod 93 Gripper bar I Disclosure II Closed position G Weight of the component p Compressed air supply / compressed air R Rotation axis of the gripper arm R1 Rotation axis of the first rod R2 axis of rotation of the drive rod V Offset of the bell crank X Linear direction

Claims

[1] Gripping device (10), comprising a compressed air cylinder (30) with a compressed air chamber (31) which can be supplied with compressed air (p) via a compressed air line (40), comprising a piston (50) arranged in the compressed air chamber (31), wherein the piston (50) can be linearly deflected against a return spring (60) by supplying the compressed air chamber (31) with compressed air (p), and the piston (50) is connected to a piston rod (51), characterized by in that the piston rod (51), which can be deflected linearly by the piston (50), is connected via a deflection lever (52) to at least one gripper arm (20) and / or to a locking mechanism (80) for actuating at least one externally driven gripper arm (21), wherein the externally driven gripper arm (21) is locked in an open position (I) by the non-actuated locking mechanism (80). [2] Gripping device according to claim 1, wherein by applying compressed air (p) to the compressed air chamber (31), the at least one gripper arm (20) can be moved into an open position (I) via the piston rod (51) and / or the locking mechanism (80) can be locked in a locked state. [3] Gripping device according to claim 1 or 2, wherein in the event of a pressure drop in the compressed air chamber (31), the at least one gripper arm (20) can be moved into a closed position (II) via the return spring (60) and / or the locking mechanism (80) can be unlocked. [4] Gripping device according to one of claims 1 to 3, wherein the externally driven gripper arm (21) can be unlocked to assume a closed position (II) by the unlocked locking mechanism (80). [5] Gripping device according to claim 4, wherein the externally driven gripper arm (21) can be moved into a closed position (II) by a spring element (70) acting directly or indirectly on the externally driven gripper arm (21). [6] Gripping device according to one of claims 4 or 5, wherein the locking mechanism (80) connected to the piston rod (51) is designed to unlock a spring-loaded coupling mechanism (90) of the externally driven gripper arm (21) or an externally driven gripper arm (21) in the event of a pressure drop. [7] Gripping device according to one of claims 4 to 6, wherein the locking mechanism (80) has a pawl (81) which engages with a corresponding locking portion (82) for locking the externally driven gripper arm (21) in an open position (I). [8] Gripping device according to one of claims 4 to 7, wherein the locking portion (82) is arranged on the externally driven gripper arm (21) or on the coupling mechanism (90). [9] Safety clamping system (100) for securing a component (120), comprising at least one gripping device (10) according to one of the preceding claims.

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