Scara robot integrated into a work surface with drives for swiveling and height adjustment

Abstract

Underfloor robot with the movements of a Scara robot, characterized in that the mechanical drive system (50) for the pivoting movements (28) and vertical movements (31) of the arms (3) and (4) or (17) and (18) is arranged below a work plate (7) of a base frame (1) and only the Z-axis as a tubular body (2) together with the lower pivot arm (3) and the upper pivot arm (4) or (17) and (18) with the effector (5) of the Scara robot variant A and B, is located above this work plate (7).

Description

[0001] It is state of the art for robots, especially SCARA robots, to be installed as stand-alone devices on tables or base frames at working height.

[0002] This creates a space requirement for the Z-axis tower (rotation axis and the Z-axis for height adjustment), which restricts the movement paths of the workpiece to be moved and also limits the space for other equipment, workpieces, test specimens or trays.

[0003] By relocating the Z-axis tower (rotation axis and the Z-axis for height adjustment) beneath the worktop of a subframe, usable space is created above the worktop. To achieve this, the entire Z-axis, with its vertical bearings and the rotary drive bearings, along with the electrical and pneumatic cables, is relocated beneath the worktop, leaving only a rotating hollow shaft protruding from the worktop. It is height-adjustable and rotatable, and the robot's arms, along with the attached effector, are mounted on the shaft.

[0004] By locating the robot drive below the worktop, all Z-axis enclosures are eliminated, and the driven Z-axis (hollow shaft) can be designed with more space. This creates a cost-effective drive system. The empty space in the base frame is optimally utilized. The worktop also forms the base frame's cover.

[0005] This results in a Z-drive structure not in the form of a linear guide and a rotating base, but rather, for example, as an axis made of hardened round tube, guided in recirculating ball bushings, which allow both linear and rotary movement. The Z-axis linear movement is carried out by a spindle, which also creates a self-locking mechanism to prevent the arms from falling in the event of a power failure. The rotation of the hollow shaft is achieved by a rotary drive that acts directly on the hollow shaft. A solid shaft running parallel to the hollow shaft in a ball bushing serves as an anti-rotation device for the drive unit.

[0006] The hollow shaft design of the Z-axis allows for electrical, control, and pneumatic cables to be routed. The length of the hollow shaft allows the cables to be rotated through an angle of ± 180 degrees. Changing the length of the hollow shaft allows the Z-stroke to be lengthened or shortened. The cable routing in the hollow shaft, which extends into the arms and extends to the effector's mounting flange, ensures that all movements of the arms and effector above the work surface are not disrupted or jammed by any cables.

[0007] The built-in anti-twist safety device prevents the robot arms from mechanically colliding with an obstacle or the human body when swiveling, and a vertically acting safety device prevents pinching when the two robot arms are lowered onto solid objects or the human body, provide so much built-in safety that it can be described as a cobot robot that allows humans and robots to work "hand in hand".

[0008] The two robot arms are arranged so that the lower robot arm is attached to the work surface and the upper arm is positioned above the lower arm. All motor drives are servo or stepper motors with backlash-free gears. The upper arms are available in two designs. Version A:

[0009] A lower robot arm is attached to one end of the vertically rotating, height-adjustable hollow shaft (Z-axis), which rotates vertically by 2 x 180 degrees. The cables and hoses routed through the hollow shaft exit into this lower robot arm. A second pivoting robot arm is attached to the other end. At its front end (center point), the second robot arm has a standard, rotatable flange facing the worktop, to which an effector suitable for the application can be attached. The robot arms can be constructed in a limited length. This design corresponds to a 4-axis SCARA robot. Version B:

[0010] A lower robot arm is attached to one end of the height-adjustable hollow shaft, which rotates vertically through 2 x 180 degrees. The cables and hoses routed through the hollow shaft end therein. A first, pivoting robot arm is attached to the front end of this lower robot arm. This robot arm has a rotary gear at its opposite end, with which the second, upper robot arm can be rotated through 180 degrees around the horizontal axis. This second, upper robot arm has a rotatable standard flange facing the worktop at its front end (center point), which can be used to rotate through 2 x 180 degrees and to which an effector suitable for the application can be attached. The robot arms can be supplied in a limited length as required. The standard overall length is 500 mm. Other required overall lengths are variable. This version represents a 5-axis SCARA robot.

[0011] The robot system is mounted on its own smaller support plate, whose footprint corresponds to the entire drive system and its safety features. This plate is then inserted and secured flush into the work surface of the base frame. This creates a large, flat work surface that covers the base frame.

[0012] The complete so-called Z-axis with rotation and height is located in the base frame.

[0013] The invention is explained in more detail using the following figures: Fig. 1 shows the overall view of the underground robot with open maintenance door for a SCARA 4-axis version. Fig. 2 shows the overall view of the underground robot with open maintenance door for a Scara 5-axis version. Fig. 3 shows a side view of the complete robot drive system mounted on the support plate for insertion into the base frame. Fig. 4 shows a view of the complete robot drive system from below. Fig. 5 shows the two arms of the underground robot for variant A with partially cut-open sections including the effector Fig. 6 shows the two arms of the underground robot for variant B with partially cut-open sections including the effector

[0014] Fig. Figure 1 shows an overall view of an underground robot variant A in a 4-axis design, with the base frame (1) supported by four lockable support and swivel rollers (8). Above the work plate (7) of the base frame (1), the hollow shaft (2) serves as the Z-axis and is connected to one end of the lower swivel arm (3). A third-party workpiece 13 is indicated lying on the work plate (7).

[0015] When the maintenance door (9) is open, the underground robot (6) is visible. The removable control panel (12) is located below the work surface (7) on the side of the base frame (1), as are the electrical mains connection (16) and the compressed air connection (15). The positioning plate (11) is attached to the rear of the base frame (1). This plate is used to fix the position of the base frame (1) with the positioning plate (10) on a third-party machine. A third-party workpiece (13) to be machined is depicted on the work surface (7). An emergency stop button (14) is provided for emergency shutdown.

[0016] Fig. 2 represents the same view as Fig. 1, but with the difference that the arms are shown according to the described variant B as a 5-axis version.

[0017] Fig. Figure 3 shows a side view of the robot drive system (50) with the hollow shaft (2) for the pivoting movement (28) as well as its vertical movement (31), shown without the substructure (1). The robot drive system (50) is mounted on the support plate (21) and the flanged guide block (30), which carries the recirculating ball bushings (33) for the hollow shaft (2). The ball bushing (34) for the anti-rotation shaft (35) is seated in the bearing housing (29) on the bearing block (39). The drive motor (32) for the recirculating ball screw (38) and its bearing (36) are mounted on the guide block (30).

[0018] The housing (29) for the ball bushing (3)4 for the anti-rotation shaft (35), the pivot bearing (44) of the hollow shaft (2), the spindle nut (37) of the recirculating ball screw (38), integrated into a vertically acting safety device (43) mounted on compression springs (45) and a limit switch (54), and the drive motor (42) with drive belt (40) for the pivoting movement (28) of the hollow shaft (2) are located on the upwardly and downwardly moving bearing block (39). A cable guide chain (41) is used to guide the cables, lines, and hoses.

[0019] Fig. 4 shows the robot drive system (50) from the underside of the bearing block (39) with the drive motor (42), on whose output shaft (22) there is a safety clutch (46) with a disengaging movement, which carries a limit switch (54) for automatic shutdown when the limit switch (54) is rotated out of the groove (52) and switches off the drive motor (42) when an obstacle is encountered when the arms (3), (4), (17) and (18) are pivoted.

[0020] From this safety coupling “swivel” (46) with small toothed belt pulley (48), the rotary movement (28) is transferred via a toothed belt (47) to a large toothed belt pulley (49), which sits directly on the hollow shaft (2), thus generating the swivel movement (28).

[0021] The changing lengths of the cables, lines and hoses caused by the vertical movement (31) of the bearing block to the guide block are compensated by a cable guide chain (41) which compensates for the variable distance between the guide block (30) and the bearing block (39).

[0022] Fig. Figure 5 shows the hollow shaft (2) with the lower swivel arm (3), at the other end of which is located a geared motor (20) with an output shaft (22). This output shaft (22) supports the upper swivel arm (4) at one end. At the other end of the upper swivel arm (4) is another geared motor (20) with an output shaft (22), positioned at the center point (26) of the upper swivel arm (4), on which a standard flange (23) is mounted, which rotates about its vertical axis (25) by ±180 degrees and onto which an effector (5) tailored to the application can be mounted.

[0023] Fig.Figure 6 shows the hollow shaft (2) supporting the lower pivot arm (3). This supports the upper pivot arm (17) via the output shaft (22) of the backlash-free gear motor (20), positioned in the lower pivot arm (3). A backlash-free gear motor (20) is positioned in this upper pivot arm (17), whose horizontal output shaft (19) supports the upper rotary arm (18), which can be rotated by 180 degrees around a horizontal axis (19). This upper rotary arm (18), in turn, supports a rotary gear (20), which, via its output shaft (22), drives a standard flange (23), thus allowing the effector (5) to rotate by 2 x 180 degrees around the vertical axis (25). LIST OF REFERENCE SYMBOLS 1 base frame, base frame 2 hollow shaft (Z-axis) 3 Lower swivel arm 4 Upper swivel arm 5 Effector 6 underground robots 7 Worktop 8 lockable castors 9 Maintenance door 10 Positioning plate on third-party machine 11 Positioning plate on underfloor robot 12 Control panel 13 Third-party workpiece 14 emergency stop buttons 15 Compressed air connection 16 Mains connection with 230V mains plug 17 Upper swivel arm 18 Upper rotating arm 19 horizontal output shaft 20 Gear motor 21 Carrying plate 22 Output shaft 23 Flange 24 not available 25 Vertical axis 26 Centerpoint 27 not available 28 Swivel movement of the hollow shaft 29 Bearing of the anti-rotation shaft 30 guide block 31 Vertical movement of the hollow shaft 32 Drive motor for vertical spindle 33 recirculating ball bushing 34 rifle 35 Anti-rotation shaft 36 Bearing for ball screw 37 spindle nut 38 ball screw 39 Bearing block 40 drive belts 41 Cable guide chain 42 Drive motor for swivel movement 43 Safety device 44 Rotary bearing of the hollow shaft 45 compression springs 46 Safety coupling swivel 47 Timing belt 48 Timing belt pulley small 49 Timing belt pulley large 50 Robot drive system 51 Control unit 52 grooves 53 Driving clutch 54 limit switches 55 vertical axis

Claims

[1] Underfloor robot with the movements of a Scara robot, characterized by that the mechanical drive system (50) for the pivoting movements (28) and vertical movements (31) of the arms (3) and (4) or (17) and (18) is arranged below a work plate (7) of a base frame (1) and only the Z-axis as a tubular body (2) together with the lower pivot arm (3) and the upper pivot arm (4) or (17) and (18) with the effector (5) of the Scara robot variant A and B, is located above this work plate (7). [2] Device according to claim 1, characterized by that the drive system (50) for the swivel movement and height movement is mounted on a support plate (21) in the size of the footprint of the robot drive system (50) and this can be installed flush with the work surface (7) of a base frame (1). [3] Device according to claim 1 and 2, characterized bythat this work plate (7) can be formed by the cover plate of a closed housing (base frame 1) and that this forms an opening into which a support plate (21) with the complete mechanics of the robot drive system can be installed. [4] Device according to claims 1-3, characterized by that the base frame (1) is a closed, watertight housing and that the internal volume of the base frame is dimensioned such that both the entire mechanics of the robot drive system (50) and the associated control unit (51) can be accommodated in the interior [5] Device according to claims 1-4, characterized by that the closed housing (base frame 1) has at least four lockable rollers (8) for sideways movement. [6] Device according to claims 1-5, characterized bythat the closed housing (base 1) has an externally mounted mechanical device (11) and (10) which ensures the repeatable positioning of the base (1) and thus of the robot on machines or other equipment. [7] Device according to claims 1-6, characterized by that the base frame (1) represents a closed, watertight housing and at the same time accommodates the electrical control unit (51) for the drive system (50) of the Scara drives in height adjustment and rotary movement without additional housing and has a maintenance door (9) through which maintenance work can be carried out both for the mechanics of the robot drive system (50) and for the control unit (51). [8] Device according to claims 1-7, characterized by that only a 230V mains voltage (16) or a 6bar compressed air line (15) is fed into the base frame (1). [9] Device according to claims 1-8, characterized bythat the lower swivel arm (3) of the underground robot variant A and / or variant B sits on a rotatable, vertically adjustable tubular body (2) and in which all necessary energy and control lines and pneumatic lines can be guided to the lower swivel arm (3) and from there to the flange (23) and the effector (5). [10] Device according to claims 1-9, characterized by that an upper swivel arm (4) is mounted at the end of the lower swivel arm (3) via the output shaft (22) of a rotary drive (20) and thereby carries out its swivel movements and that in the upper swivel arm (4) at the end (center point 26) there is a rotary drive (20) on whose output shaft (22) there is a rotatable flange (23) on which the effector (5) can be mounted. [11] Device according to claims 1-10, characterized bythat an upper swivel arm (4) is mounted at the end of the lower swivel arm (3) via the output shaft (22) of a rotary drive (20) and thereby carries out its swivel movements and that in the upper shortened swivel arm (17) there is a gear (20) with a horizontal output shaft (19), on which a further upper swivel arm (18) is seated and is thus rotated about its horizontal axis by the gear motor (20) and in the upper swivel arm (18) at the end of which (center point 26) there is a rotary drive (20) on whose output shaft (22) there is a rotatable flange (23) on which the effector (5) can be mounted. [12] Device according to claims 1-11, characterized by that the hollow shaft (2) has a drive motor (42) which drives and positions the hollow shaft (2) rotating / pivoting (28) about its vertical axis (55) via a toothed belt (47) and the toothed belt pulleys (48) and (49). [13] Device according to claims 1-12, characterized byin that, to protect against injury or crashes caused by arms (3) and (4) or (17) and (18) sitting on the hollow shaft (2) and pivoting, a safety clutch (46) is mounted on the toothed belt pulley (48) sitting on the output shaft (22) of the drive motor (42), said safety clutch consisting of a spring-loaded mechanical driving clutch (53) and having a limit switch (46) and a groove (52) which rotate relative to one another when an obstacle is encountered and which switches off and mechanically disengages the drive motor (42) via the limit switch (54) and finds its groove (52) and its starting position again after re-engaging in the starting position. [14] Device according to claims 1-13, characterized bythat for the vertical movement of the hollow shaft (31) a ball screw (38) arranged parallel to the hollow shaft (1), driven by a drive motor (32), is installed and its corresponding spindle nut (37) is mounted on the bearing block (39) by means of springs (45), so that when the swivel arms (3) and (4), or (17) and (18) vertically impact a body part, e.g. arm of an operator or another obstacle, the spindle nut (37) can spring axially and the drive motor (32) is switched off via a limit switch (54). [15] Device according to claims 1-14, characterized bythat two selected recirculating ball bushings (33), which are located in the guide block (30) which is fastened to the support plate (21) and which is installed with the same area in the work plate (7) of the base frame (1), allow degrees of freedom for the linear movement (31) as well as the rotary movement (28) and thus represent a simplification of the mechanical structure of a vertical movement (31) and rotary movement (28) of a robot. [16] Device according to claims 1-15, characterized by that a guide element, preferably a shaft (35), is provided parallel to the hollow shaft (Z-axis) (2), which prevents the bearing block (39) from rotating during the vertical movement (31) and pivoting movement (28). [17] Device according to claims 1-16, characterized bythat the character of a cobot is created by safety devices that monitor the vertical direction and the pivoting of the arms, and thus all additional safety devices such as covers above the worktop or light curtains can be dispensed with.

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