Swivel joint for a robot

Abstract

The present invention relates to a slewing joint (1) for a robot, comprising a double-acting pneumatic slewing actuator (2) having a first work chamber (51) having a first work port (53) and a second work chamber (52) having a second work port (54), a first valve group designed to selectively connect the first work port (53) to a ventilation port (14) and an exhaust port (15), a second valve group (9) designed to selectively connect the second work port (54) to a ventilation port (14) and an exhaust port (15), and a valve array (7) including safety valves (11, 12) connected to the first work port (53) and the second work port (54), designed to cut off the connection between the first work port (53) and the second work port (54) in a cut-off position and to release the connection between the first work port (53) and the second work port (54) in an open position.

Description

Technology Field

[0001] The present invention relates to a slewing joint for a robot, comprising a pneumatic slewing actuator designed to be double-acting, having a first working chamber with a first working port and a second working chamber with a second working port, and a valve array designed for safety-related pneumatic control of the slewing actuator. Background Technology

[0002] DE 10 2019 211 992 A1 discloses a fluid actuator comprising a first pressure chamber and an actuator member to which a fluid driving force can be applied so as to change the position of the actuator member by supplying a pressure fluid to the first pressure chamber; a control valve device designed to connect the first pressure chamber to a pressure fluid supply line to selectively supply pressure fluid to the first pressure chamber or to a pressure fluid sink to discharge pressure fluid from the first pressure chamber; and a fluid system comprising a safety device for providing a safe state in which no fluid driving force is applied to the actuator member, wherein the safety device comprises a first check valve and a safety valve unit connected in parallel to the control valve device between the first pressure chamber and the pressure fluid supply line, and the safety valve unit is designed to connect the pressure fluid sink and the pressure fluid supply line at a safe switching position so that pressure fluid present in the first pressure chamber can be discharged into the pressure fluid sink through the first check valve and the pressure fluid supply line to provide a safe state. The problem to be solved

[0003] The objective of the present invention is to provide a slewing joint for a robot capable of realizing improved safety requirements that must be observed during direct cooperation between a robot and a human. means of solving the problem

[0004] The above problem is solved for a swivel joint of the aforementioned method by including a first valve group designed to selectively connect a first work port to a ventilation port and an exhaust port, a second valve group designed to selectively connect a second work port to a ventilation port and an exhaust port, and a safety valve connected to the first work port and the second work port, designed to cut off the connection between the first work port and the second work port in the cut-off position and to release the connection between the first work port and the second work port in the release position.

[0005] A valve array is used to ensure the controlled pressurization and ventilation of the first and second working chambers of a pneumatic slewing actuator, said two working chambers are sealedly separated from each other by a slewing vane slewingly accommodated within the actuator housing and are each designed to be variable in size. The slewing vane is connected to an output shaft so that the slewing movement of the slewing lever relative to the actuator housing can be transmitted to a subsequent component, such as a subsequent arm section, for example, of a robot arm.

[0006] Accordingly, the slewing actuator can be used to slewing the subsequent arm section of a robot arm relative to the preceding arm section of a robot arm coupled to the actuator housing of the pneumatic slewing actuator in a normal operating state of the slewing joint. During this normal operating state, a pressure difference between the first working chamber and the second working chamber is created using the first valve group and the second valve group, thereby generating a predetermined slewing movement of the slewing vane relative to the actuator housing and the output shaft connected thereto. Additionally, the first valve group and the second valve group can be used to equalize the fluid pressure of the first working chamber and the fluid pressure of the second working chamber, thereby causing the pneumatic slewing actuator to stop.

[0007] A safety valve is assigned to the pneumatic slewing actuator because, during the operation of a robot equipped with at least one such slewing joint, dangerous situations and failures that may occur due to, for example, the malfunction of the first valve group and / or the second valve group must be prevented. This safety valve can be triggered, for example, by operating an emergency stop switch by a user working with the robot to switch the pneumatic slewing actuator to a safe state as quickly as possible. This safe state may, for example, be such that the movement of the pneumatic slewing actuator and the arm parts of the robot arm connected thereto is stopped as quickly as possible.

[0008] In order to quickly and reliably ensure this safety state, the safety valve is connected to the first work port and the second work port and is designed to release the fluid communication connection between the first work port and the second work port in the release position. The safety valve takes this release position, for example, after the operation of an emergency stop switch. In contrast, during normal operation, the safety valve takes a shut-off position in which the blockage of the fluid communication connection between the first work port and the second work port is ensured.

[0009] From a pneumatic perspective, the role of the safety valve is to induce rapid pressure equalization between the first and second working chambers of the pneumatic slewing actuator in the release position. As a result, any subsequent slewing movement of the slewing actuator is prevented, because the pressure difference between the first and second working chambers required for further movement is reduced as quickly as possible.

[0010] Therefore, the role of the safety valve is to ensure a fluid communication connection between the first work port and the second work port in the released position and to eliminate the pressure difference between the first work chamber and the second work chamber. Additionally, in the closed position, the safety valve is configured to allow a pressure difference to be formed between the first work chamber and the second work chamber using the first valve group and the second valve group, in which case the fluid communication connection between the first work port and the second work port is blocked.

[0011] Preferably, the safety valve is designed as a switching valve, and control of the safety valve may be optionally provided electrically or fluidically. For example, the safety valve is designed as a magnetic valve or as a fluid-technical pilot-controlled valve. Particularly preferably, the safety valve is positioned right near the slewing actuator to ensure a rapid response time for pressure equalization between the first working chamber and the second working chamber through the shortest possible fluid line length.

[0012] A preferred improvement of the present invention is the subject of a dependent claim.

[0013] It is desirable that the safety valve be connected to the exhaust port and designed to block the connection between the first and second working ports and the exhaust port in the blocked position, and that the safety valve be designed to release the connection between the first and second working ports and the exhaust port in the released position. By connecting the first and second working ports to the exhaust port, it is achieved to lower the pressure level in the first and second working chambers in addition to the pressure equalization between the first and second working chambers. Thus, the slewing actuator, which has already reached a safe state due to the pressure equalization between the first and second working chambers, is converted to a zero-energy state within a structurally predetermined cycle required to reduce the overpressure present in the first and second working chambers relative to the ambient pressure, and consequently, a higher level of safety for the slewing joint can be realized.

[0014] In this case, the safety valve is configured such that a pressure drop already occurs in the two working chambers during the pressure equalization process between the first working chamber and the second working chamber. This pressure drop continues even after pressure equalization between the two working chambers until a pressure level is achieved in the two working chambers that is at least nearly equivalent to the ambient pressure around the slewing joint.

[0015] For example, the safety valve is designed as a 3 / 2-distribution valve in which no fluid communication is established between a total of three valve ports in the closed position, while a fluid communication is ensured between all three valve ports in the released position. Preferably, a first working port is connected to the first valve port of the safety valve, a second working port is connected to the second valve port of the safety valve, and an exhaust port is connected to the third valve port of the safety valve.

[0016] It is preferable for the safety valve to have an actuator for switching between an open position and a closed position, and for the safety valve to have a spring designed for the prestress of the safety valve in the open position. The role of the actuator is to switch the safety valve between the open position and the closed position. The actuator is a component of the safety valve and acts on a valve member movably received in the valve housing of the safety valve. For example, the predetermined closing or opening of a fluid communication connection between three valve ports of the safety valve is controlled by this valve member. For example, a valve seat may be formed within the valve housing that is opened or closed depending on the position of the valve member, thereby affecting the closing or opening of the fluid communication connection between the valve ports.

[0017] Since the actuator that can be used to move the valve member is, for example, an electromagnetic drive, the safety valve is designed as a magnetic valve, or since the actuator is a fluid drive, the safety valve is designed as a fluid-technical pilot-controlled valve. Accordingly, electrical or fluid-technical control of the actuator must be provided. For example, other valve designs using piezoelectric benders, piezoelectric stacks, or other active valve members may also be considered.

[0018] For example, the valve member is designed with spring elasticity and receives prestress in the release position. Alternatively, the valve member is assigned a separately designed spring that ensures the prestress of the valve member in the release position.

[0019] In any case, the safety valve is provided to assume a release position in a no-energy state where electrical or pneumatic control of the actuator is not provided. As a result, in cases where the intended control of the actuator is impossible, such as in the event of a power outage and / or failure of the pneumatic supply, the safety state for the slewing actuator is pre-supported by the configuration of the safety valve.

[0020] In another embodiment of the present invention, a throttle is provided to be positioned between the safety valve and the exhaust port. The role of the throttle is to ensure a prescribed pressure reduction within the first working chamber and the second working chamber before and after the performance of pressure equalization between the first working chamber and the second working chamber.

[0021] Preferably, the throttle cross-section of the throttle is selected to be larger than the supply cross-section of the first valve group and larger than the supply cross-section of the second valve group. By taking this measure, in the event of a malfunction in the first valve group and / or the second valve group, when the safety valve is in the release position, a symmetrical increase in pressure in the two working chambers is prevented due to the maintenance of the compressed air supply to the first working chamber or the second working chamber. Rather, even in such cases, by connecting the first working port and the second working port to the exhaust port, pressure equalization between the first working chamber and the second working chamber, as well as a predetermined pressure reduction in the first working chamber and the second working chamber, is ensured.

[0022] It is desirable to provide two switching valves connected in parallel to allow fluid passage. If only a first fault case, in which a safety valve malfunction must also be considered, is considered for the swivel joint, the use of two safety valves connected in parallel to allow fluid passage can eliminate hazardous situations caused by the swivel joint in the case of such a first fault. Particularly preferably, the two safety valves connected in parallel to allow fluid passage are implemented with different control units and / or different valve technologies so that various redundancies of the safety valves can be ensured.

[0023] It is desirable that a first control device, separately designed, is assigned to one of the two safety valves and that the control device is designed to control the actuator of this safety valve, and that a second control device, separately designed, is assigned to the other of the two safety valves and that the control device is designed to control the actuator of this safety valve. By designing the control devices separately for the two actuators of the two safety valves, a failure of one control device should be prevented from causing failure of the two safety valves, as may occur in a single common control device. Furthermore, by designing the two control devices separately, individual control of the actuators, each assigned to the required type of energy (electricity, compressed air), becomes simply possible.

[0024] In a preferred improved embodiment of the present invention, a first pressure sensor designed to provide a first pressure signal to a first control device is assigned to a first work port or a first work chamber, and a second pressure sensor designed to provide a second pressure signal to a second control device is assigned to a second work port or a second work chamber. Thus, the pressure level at each work port or each work chamber can be determined by the first pressure sensor and the second pressure sensor, which is particularly important for checking the function of the safety valve and, if applicable, the throttle placed downstream of each. For example, a pressure change for each work chamber can be determined after the triggering of the safety function and simultaneously after the switching of the safety valve from the shut-off position to the release position, and, if applicable, the pressure change can be compared with a predetermined pressure change to enable verification of whether damage to the safety valve or the throttle exists.

[0025] It is preferable that a brake and a brake control unit, which are prestressed to a braking position, are assigned to a slewing actuator, and that the brake control unit is designed to switch the brake between a braking position and a release position for the slewing actuator. The role of the brake and the associated brake control unit is to brake or completely stop the slewing movement of the slewing actuator. To this end, the brake, provided for frictional and / or shape-fit contact with the moved component of the slewing actuator in the braking position, has an internal prestress toward the braking position, so that the brake is maintained in the braking position by the brake control unit without the supply of electrical or pneumatic energy. Accordingly, the brake control unit is designed to switch the brake from the braking position to the release position and to cause this transition by providing electrical or fluid energy to the brake. Preferably, the brake comprises a spring device, in particular a threaded coil spring, a leaf spring device, or an air spring, and is provided to be prestressed to the braking position by the spring energy stored in this spring device.

[0026] Additionally, the brake has a fluid-sealed working chamber, and the size of said chamber is provided such that it can be changed by pressurization so that a brake member associated with the brake is switched from the braking position of the slewing actuator to the release position of the slewing actuator. Alternatively, a magnetic drive or other electric drive is assigned to the brake, and as long as electrical energy can be utilized by the brake control unit, the braking position can be released by said drive.

[0027] It is preferable that the brake control unit, the first valve group, the second valve group, the first control device, and the second control device are each electrically connected to the valve control unit for the performance of a test process, and that the valve control unit is designed such that the brake control unit causes a braking state for the slewing actuator, asymmetric pressurization of the slewing actuator is caused by the first valve group and / or the second valve group, switching of at least one safety valve from a closed position to a released position is performed, and monitoring of pressure changes at the first work port and / or the second work port is performed.

[0028] Through this test process, it can be verified whether the function of at least one of the two safety valves required to ensure the safe operation of the slewing joint is guaranteed, in particular whether the function of both safety valves is guaranteed. Only in such cases should continuous operation of the slewing joint be permitted. If, during the execution of the test process, a deviation exceeding a threshold value appears between the actual pressure change at the first working port and / or the second working port and a predetermined pressure change, in particular one stored in the valve control unit, further operation of the slewing joint is prevented by the valve control unit and an error message is output.

[0029] Preferred embodiments of the present invention are illustrated in the drawings. Brief explanation of the drawing

[0030] FIG. 1 is a schematic diagram of a slewing joint equipped with a slewing actuator and a valve array. Specific details for implementing the invention

[0031] The pivot joint (1) schematically illustrated in FIG. 1 is provided for use in an unillustrated robot arm of an industrial robot, where it is used for a pivotally movable and drivable connection between two unillustrated arm sections of the industrial robot.

[0032] In this case, the pivot joint (1) preferably forms a compact assembly that can be connected to the leading arm section and the following arm section of the robot arm completely independently, and requires only pneumatic energy supply and electric control signal supply to perform a predetermined pivot movement.

[0033] The slewing joint (1) comprises a slewing actuator (2), said actuator designed as a pneumatic slewing vane drive, and has a schematically illustrated circular cylindrical actuator housing (3) in which a slewing vane (4) is slewingly mounted inside, and a separator (5) fixedly disposed within the actuator housing (3). The slewing vane (4) is connected to an output shaft (6) coaxially disposed within the actuator housing (3), said output shaft may pass through the actuator housing (3) in a manner not illustrated and be connected outside the actuator housing (3), for example, to an unillustrated arm portion of a robot arm. Additionally, it may be provided that the actuator housing (3) is connected to an additional unillustrated arm portion of the robot arm. Accordingly, by introducing a pivoting movement to the output shaft (6), pivoting can be implemented between the actuator housing (3) and the unillustrated arm parts of the robot arm connected to the output shaft (6).

[0034] The swivel vane (4), together with the separator (5), divides the volume enclosed by the actuator housing (3) into a first work chamber (51) of variable size and a second work chamber (52) of variable size, and the size of the two work chambers (51, 52) depends on the respective swivel position of the swivel vane (4). A first work port (53) is assigned to the first work chamber (51), and ventilation and exhaust of the first work chamber (51) can be performed through said work port. A second work port (54) is assigned to the second work chamber (52), and ventilation and exhaust of the second work chamber (52) can be performed through said work port.

[0035] A brake (42) is shown purely schematically within a second working chamber (52), said brake comprises a brake housing (43) designed in a purely exemplary circular cylindrical shape having a brake piston (44) housed therein to be linearly movable and a coupling rod (45) connected to the brake piston (44), a brake block (46) connected to the coupling rod (45), and a prestress spring (47) housed between the brake piston (44) and the brake housing (43). The brake housing (43) encloses a variable-size fluid working chamber (48) together with the brake piston (44) and the coupling rod mounted in a sealed manner to the brake housing (43), said working chamber may be optionally ventilated or exhausted through a third fluid line by a brake control unit (41), and as a result, linear relative movement of the brake piston (44), the coupling rod (45) connected thereto, and the brake block (46) may be caused. The prestress spring (47) is designed to apply shape-fit coupling and / or frictional force to the output shaft (6) by pressing the brake block (46) against the output shaft (6) when the fluid working chamber (48) is exhausted. When the fluid working chamber (48) is ventilated, the prestress spring (47) is compressed, and linear displacement of the brake piston (44) occurs together with the coupling rod (45) and the brake block (46), thereby removing the shape-fit coupling and / or frictional force to the output shaft (6).

[0036] For ventilation and exhaust of the first work chamber (51), the first work port (53) is connected to the first fluid line (71), and the fluid line is connected to the first line section (81). For ventilation and exhaust of the second work chamber (52), the second work port (54) is connected to the second fluid line (72), and the fluid line is connected to the second line section (82).

[0037] The first line section (81) is connected to both the first control valve (31) and the second control valve (32) forming the first valve group (8). The second line section (82) is connected to both the third control valve (33) and the fourth control valve (34) forming the second valve group (9). The control valves (31 to 34) are designed purely as exemplarily 2 / 2-distribution switching valves. The control valves (31 and 33) are connected to the first stop valve (35) through the third line section (83) and the fifth line section (85), and the stop valve is connected to the fourth line section (84) through the seventh line section (87). Additionally, the first stop valve (35) is connected to the second stop valve (36) through the eighth line section (88), and the stop valve is connected to the compressed air source (16) assigned to the ventilation port (14) through the sixth line section (86) and to the seventh line section (87) through the ninth line section (89). For example, the first stop valve (35) and the second stop valve (36) are each designed as 3 / 2-distribution switching valves.

[0038] Through the aforementioned fluid-through interconnection of the first stop valve (35) and the second stop valve (36), the fifth line section (85) is optionally connected to the fourth line section (84) in a fluid-communication manner, thereby causing exhaust of the fifth line section (85). Alternatively, if both the first stop valve (35) and the second stop valve (36) are switched from the exhaust position shown in FIG. 1 to an unillustrated ventilation position, the fifth line section (85) may be connected to the compressed air source (16) in a fluid-communication manner. Thus, the two stop valves (35, 36) are components of the safety-related compressed air supply for the slewing actuator (2), because, for the operation of the slewing actuator (2), it must first be ensured that the redundantly placed stop valves (35, 36) function correctly.

[0039] When the first control valve (31) is switched from the shut-off position shown in FIG. 1 to an unillustrated release position, a fluid communication method connection between the third line section (83) and the first line section (81) can be formed by the first control valve (31). In this case, when the two stop valves (35, 36) are also switched to an unillustrated ventilation position, ventilation of the first work chamber (51) through the first line section (81) and the first fluid line (71) becomes possible. In a similar manner, this also applies to the function of the third control valve (33) in relation to ventilation of the second work chamber (52) through the second line section (82) and the second fluid line (72).

[0040] When the second control valve (32) is switched from the closed position shown in FIG. 1 to an unillustrated open position, a fluid communication method connection can be formed between the first line section (81) and the fourth line section (84), which is used as a pressure fluid sink by the second control valve (32) and connected through the tenth line section (90) to a compressed air outlet having a silencer (17). As a result, exhaust of the first work chamber (51) through the first line section (81) and the first fluid line (71) becomes possible. In a similar manner, this also applies to the function of the fourth control valve (34) in relation to exhaust of the second work chamber (52) through the second line section (82) and the second fluid line (72).

[0041] As can be further seen from FIG. 1, the first valve port (61) of the first safety valve (11) is connected to the first fluid line (71) through the 11th line section (91). Additionally, the second valve port (62) of the first safety valve (11) is connected to the second fluid line (72) through the 13th line section (93). The third valve port (63) of the first safety valve (11) is connected to the first throttle (25) through the 14th line section (94), and the throttle is connected in a fluid communication manner to the 10th line section (90) and the exhaust port (15) through the 15th line section.

[0042] In a similar manner, the first valve port (64) of the second safety valve (12) is connected to the first fluid line (72) through the 12th line section (92), the second valve port (65) is connected to the second fluid line (72) through the 16th line section (96) and the 13th line section (93), and the third valve port (66) is connected to the second throttle (26) through the 17th line section (97). The second throttle (26) is connected to the exhaust port (15) through the 18th line section (98) and the 15th line section (95).

[0043] Purely by example, the first safety valve (11) and the second safety valve (12) are each designed as 3 / 2-distribution switching valves. A first actuator (23) is assigned to the safety valve (11), and the actuator enables, purely by example, the combined operation of the first safety valve (11) by the magnetic valve and the fluid-technical pilot control unit coupled thereto. The first actuator (23) is electrically connected to a first control unit (21) via a first control line (74), and the control unit is designed to provide an electrical control signal to the first actuator (23). In a similar manner, a second actuator (24) is assigned to the second safety valve (12), and the actuator enables, purely by example, the combined operation of the second safety valve (12) by the magnetic valve and the fluid-technical pilot control unit coupled thereto. The second actuator (24) is electrically connected to the second control device (22) via the second control line (75), and the control device is designed to provide an electrical control signal to the second actuator (24). A first return spring (67) is assigned to the first safety valve (11), and the return spring switches the first safety valve (11) from the closed position shown in FIG. 1 to an unillustrated release position as soon as the first actuator (23) can no longer be controlled. A second return spring (68) is assigned to the second safety valve (12), and the return spring switches the second safety valve (12) from the closed position shown in FIG. 1 to an unillustrated release position as soon as the second actuator (24) can no longer be controlled.

[0044] Additionally, to provide an electric sensor signal to the first control device (21), the first pressure sensor (27) is electrically connected to the first control device (21) via the first sensor line (29). The first pressure sensor (27) is connected to the first fluid line (71) to allow fluid to pass through, thereby enabling pressure detection at the first work port (53). To provide an electric sensor signal to the second control device (22), the second pressure sensor (28) is electrically connected to the second control device (22) via the second sensor line (30). The second pressure sensor (28) is connected to the second fluid line (72) to allow fluid to pass through, thereby enabling pressure detection at the second work port (54).

[0045] The first control unit (21) is electrically connected to the valve control unit (10) via the third control line (76), and the valve control unit is designed for coordinated control of the first control unit (21) of the valve group (19) including control valves (31 to 34) and stop valves (35 and 36) connected via the fifth control line (78), the second control unit connected via the fourth control line (77), and the brake control unit (41) connected via the sixth control line (79). The valve group (19) forms a valve array (7) together with safety valves (11 and 12).

[0046] The valve control unit (10) may be connected to a robot control unit (not shown), for example, and a separately designed safety control unit. In this case, the robot control unit may provide control commands to the valve control unit (10) for normal operation of the pivot joint (1), while the safety control unit may provide, for example, an emergency stop signal to the valve control unit (10). The control commands may indicate the movement of the pivot actuator (2) and the stop state of the pivot actuator (2), particularly using the brake (42). The emergency stop signal indicates an emergency stop for the pivot actuator (2), which is described in more detail below.

[0047] In the normal operating state of the pivot joint (1), the valve control unit (10) receives a control command from the upper robot control unit and converts this control command into a pressure setting value for, for example, the first work chamber (51) and the second work chamber (52), and the pressure setting value is provided to the valve group (19) through the fifth control line. To monitor the predetermined pressure setting value, the valve control unit (10) may investigate the sensor signals of the first pressure sensor (21) and the second pressure sensor (28) from each control device (21 and 22), and as a result, pressure control for the operating pressure in the first work chamber (51) and the operating pressure in the second work chamber (52) may be provided. When a suitable pressure difference is provided between the first work chamber (51) and the second work chamber (52), the pivoting vane (4) is pivotally moved, and thus the pivotally relative movement of the unillustrated arm part of the robot arm coupled to the output shaft is made with respect to the unillustrated other arm part of the robot arm coupled to the actuator housing (3).

[0048] When a stop state of the slewing joint is required by the robot control unit, the valve control unit (10) may optionally cause a pressure increase or a pressure decrease in one of the two working chambers (51, 52) so that the pressure difference between the two working chambers (51 and 52) may be reduced, provided that no further movement of the slewing vane (4) occurs. Additionally, the valve control unit (10) may provide a control signal to the brake control unit (41) via the sixth control line (79), and the brake control unit may cause the fluid working chamber (48) to be exhausted so that the brake block (46) comes into contact with the drive shaft (6) in a shape-fit and / or friction-fit manner.

[0049] When an emergency stop signal is provided to the valve control unit (10) by the robot control unit, all valves of the valve group (19), namely control valves (31 to 34) and control valves (35 and 36), are moved to the position shown in FIG. 1. Thus, fluid flow in line sections (81 and 82) is no longer possible, and no fluid inflow or outflow occurs from the valve group (19) to the two fluid lines (71 and 72).

[0050] Additionally, the valve control unit (10) controls the first control device (21) and the second control device (22) immediately upon arrival of an emergency stop signal, so that the first safety valve (11) and the second safety valve (12) can each be switched from the closed position shown in FIG. 1 to an unillustrated release position. As soon as at least one of the two safety valves (11, 12) is in the release position, a fluid communication connection exists between the first working chamber (51) and the second working chamber (52), and consequently, pressure equalization between the two working chambers (51, 52) is achieved. This pressure equalization prevents further swivel movement of the swivel vane (4). Additionally, pressure reduction occurs in the two working chambers (51 and 52) that are connected to each other via a fluid communication method through their respective assigned throttles (25, 26), and consequently, pressure energy reduction occurs in the two working chambers (51, 52).

[0051] Additionally, the valve control unit (10) may provide a corresponding control signal to the brake control unit (41) upon arrival of an emergency stop signal, thereby causing exhaust of the fluid working chamber (48) of the brake (42) and thus introducing a braking force to the output shaft (6).

[0052] When the pivot joint (1) is operated, and additionally at regular intervals, a test process may be performed, and in this test process, the valve control unit (10) first causes a braking action on the output shaft (6) by appropriate control of the brake control unit (41), and then causes asymmetric pressurization for the first work chamber (51) and the second work chamber (52) by appropriate control of the valve group (19). In the next step, the valve group (19) is switched to a blocked state as shown in FIG. 1. Then, the two safety valves (11 and 12) are triggered by appropriate control of the first control unit (21) and the second control unit (22), and in this case, the valve control unit (10) can detect a change in pressure equalization between the first work chamber (51) and the second work chamber (52) based on the pressure signals of the first pressure sensor (27) and the second pressure sensor (28) and can compare it with a stored change curve. If the actual change in pressure equalization largely matches the stored change curve, the test process ends positively and there is no problem with further operation of the slewing joint (1). Otherwise, if there is a deviation between the actual change and the stored change curve that exceeds the stored threshold, the valve control unit (10) outputs an error message and blocks the slewing joint (1).

[0053] To further enhance safety, the first control device (21) and the second control device (22) are electrically connected to each other via a communication line (38) which is optional and therefore illustrated as a dashed line, and can compare the control signals arriving from the valve control unit (10) with each other. In this case, the first control device (21) and the second control device (22) can be configured so that if there is a deviation between the control signals arriving from the valve control unit (10), the triggers of the first safety valve (11) and the second safety valve (12) are automatically executed to switch the slewing joint (1) to a safe state.

Claims

Claim 1 As a slewing joint (1) for a robot, a pneumatic slewing actuator (2) designed to be double-acting, having a first work chamber (51) having a first work port (53) and a second work chamber (52) having a second work port (54), a first valve group (8) designed to selectively connect the first work port (53) to a ventilation port (14) and an exhaust port (15), a second valve group (9) designed to selectively connect the second work port (54) to the ventilation port (14) and the exhaust port (15), and safety valves (11, 12) connected to the first work port (53) and the second work port (54), designed to cut off the connection between the first work port (53) and the second work port (54) in a cut-off position and to release the connection between the first work port (53) and the second work port (54) in an released position. A slewing joint having a valve array (7) designed for safety-related pneumatic control of the slewing actuator (2), including Claim 2 A pivot joint according to claim 1, wherein the safety valve (11, 12) is connected to the exhaust port (15) and is designed to block the connection between the first work port (53) and the second work port (54) and the exhaust port (15) in a blocked position, and is designed to release the connection between the first work port (53) and the second work port (54) and the exhaust port (15) in a released position. Claim 3 A slewing joint according to claim 1, wherein the safety valve (11, 12) has an actuator (23, 24) for switching between a release position and a block position, and the safety valve (11, 12) has a spring (67, 68) designed for pre-stressing the safety valve (11, 12) in the release position. Claim 4 A pivot joint characterized in that, in any one of claims 1 to 3, a throttle (25, 26) is disposed between the safety valve (11, 12) and the exhaust port (15). Claim 5 A pivot joint according to claim 4, characterized in that the throttle cross-section of the throttle (25) is selected to be larger than the supply cross-section of the first valve group (8) and larger than the supply cross-section of the second valve group (9). Claim 6 A slewing joint characterized by being provided with two safety valves (11, 12) connected in parallel to allow fluid to pass through, in any one of claims 1 to 3. Claim 7 A slewing joint according to claim 6, wherein a first control device (21) separately designed is assigned to one of the two safety valves (11), said control device is designed to control an actuator (23) of said safety valve (11), and a second control device (22) separately designed is assigned to the other of the two safety valves (12), said control device is designed to control an actuator (24) of said safety valve (12). Claim 8 A pivot joint according to claim 7, characterized in that a first pressure sensor (27) designed to provide a first pressure signal to the first control device (21) is assigned to the first work port (53) or the first work chamber (51), and a second pressure sensor (28) designed to provide a second pressure signal to the second control device (22) is assigned to the second work port (54) or the second work chamber (52). Claim 9 A pivot joint characterized in that, in claim 8, a brake (42) receiving pre-stress in a braking position and a brake control unit (41) are assigned to the pivot actuator (2), and the brake control unit (41) is designed to switch the brake (42) between a braking position for the pivot actuator (2) and a release position for the pivot actuator (2). Claim 10 A slewing joint according to claim 9, wherein the brake control unit (41), the first valve group (8), the second valve group (9), the first control device (21) and the second control device (22) are each electrically connected to the valve control unit (10), and the valve control unit (10) is designed such that, for the performance of a test process, the brake control unit (41) causes a braking state for the slewing actuator (2), asymmetric pressurization of the slewing actuator (2) is caused by at least one of the first valve group (8) and the second valve group (9), switching of at least one safety valve (11, 12) from a blocked position to a released position is performed, and monitoring of pressure change is performed at at least one of the first work port (53) and the second work port (54).

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