Positioning unit

Abstract

A positioning unit includes two control carriages and a work carriage, it being possible to move the two control carriages and the work carriage on tracks that extend in parallel with one another. There is a working arm being articulated on a work base point on the work carriage and a control arm being articulated on a control base point on each of the control carriages. The control arms are articulated on the working arm at a control point of the working arm, the control point being spaced apart at a predefined lambda distance (d) from an end of the working arm that forms a working-point end and faces away from the work base point, and the two control base points and the work base point defining a triangle. At least two carriages of the two control carriages and the work carriage are movably arranged on a shared guide.

Claims

1. A positioning unit (1, 101, 201, 301) comprising two control carriages (2, 3, 202, 203, 502) and a work carriage (4, 204, 304, 404), the two control carriages (2, 3, 202, 203, 502) and the work carriage (4, 204, 304, 404) being configured to be movable on tracks that extend in parallel with one another, a working arm (5, 305, 405) being articulated on a work base point (8, 308) on the work carriage (4, 204, 304, 404) and a control arm (6, 7) being articulated on a control base point (9, 10) on each of the control carriages (2, 3, 202, 203, 502), the control arms (6, 7) being articulated on the working arm (5, 305, 405) at a control point (11) of said working arm, the control point (11) being spaced apart at a predefined lambda distance (d) from an end of the working arm (5, 305, 405) that forms a working-point end (12) and faces away from the work base point (8, 308), and the two control base points (9, 10) and the work base point (8, 308) defining a triangle, wherein at least two carriages of the two control carriages (2, 3, 202, 203, 502) and the work carriage (4, 204, 304, 404) are movably arranged on a shared guide (13, 213, 513).

2. The positioning unit according to claim 1, wherein the work base point (8, 308) is arranged on a base plate (16, 216) of the work carriage (4, 204, 304, 404).

3. The positioning unit according to claim 1, wherein a work unit (17, 217, 317, 417, 617) is arranged at the working-point end (12) of the working arm (5, 305, 405).

4. The positioning unit according to claim 1, wherein a support arm (22, 23, 222, 223, 322, 622, 623), that is supported at least indirectly on the guide (13, 213, 513) is connected to the working-point end (12) of the working arm (5, 305, 405) and/or a work unit (17, 217, 317, 417, 617) arranged at the working-point end (12) of the working arm (5, 305, 405).

5. The positioning unit according to claim 1, wherein a first and/or a second support arm (22, 23, 222, 223, 322, 622, 623) form a parallelogram mechanism together with the working arm (5).

6. The positioning unit according to claim 4, wherein the support arm (22, 23, 222, 223, 322, 622, 623) is arranged so as to be movable relative to at least one other carriage.

7. The positioning unit according to claim 1, wherein the support arm (22, 23, 222, 223, 322, 622, 623) is a flexible tension element.

8. The positioning unit according to claim 1, wherein at least two of the carriages are arranged on a base carriage, the at least two carriages being movable relative to one another.

9. The positioning unit according to claim 1, wherein the positioning unit (1, 101, 201, 301) has an impulse decoupling unit (537), for decoupling or respectively compensating for a recoil impulse.

10. The positioning unit according to claim 1, wherein the positioning unit (1, 101, 201, 301) has a weight compensation unit (638).

11. The positioning unit according to claim 1, wherein at least one articulation is formed by means of a preloaded bearing.

12. The positioning unit according to claim 1, wherein at least one of the carriages is movable by means of a linear motor, a current-carrying motor part (535) of the linear motor being arranged on the carriage.

13. The positioning unit according to claim 1, wherein at least two of the carriages share a component of the positioning unit.

14. The positioning unit according to claim 1, wherein the positioning unit (1, 101, 201, 301) has a control unit that is a computer unit and is configured to move the control (2, 3, 202, 203, 502) and/or the work carriages (4, 204, 304, 404) along the guide (13, 213, 513) such that the working-point end (12) reaches a predefinable spatial position within a working space (24) of the positioning unit (1, 101, 201, 301).

Description

(1) Embodiments of the invention are shown in the schematic drawings and are explained in further detail in the following description.

(2) In the drawings:

(3) FIG. 1 is a perspective view of a first positioning unit;

(4) FIG. 2 is a schematic representation of a positioning unit that is assembled analogously to the positioning unit in FIG. 1;

(5) FIG. 3 is a schematic representation of a third positioning unit having four controllable axes;

(6) FIG. 4 is a schematic representation of a fourth positioning unit having four controllable axes;

(7) FIG. 5 is a schematic representation of a parallelogram mechanism formed by flexible tension elements;

(8) FIG. 6 is a schematic representation of an impulse decoupling unit;

(9) FIG. 7 is a schematic representation of a weight compensation unit.

(10) FIG. 1 is a perspective view of a first positioning unit 1. Two control carriages 2, 3 and a work carriage 4 can be seen. On the work carriage 4, a working arm 5 is articulated on a work base point 8. On the control carriages 2 and 3, control arms 6, 7 are articulated on control base points 9, 10, respectively.

(11) The control arms 6, 7 are additionally articulated on the working arm 5 at a control point 11. For this purpose, the control point 11 has a universal joint combined with a rotational joint.

(12) The control point 11 is spaced apart from a working-point end 12 of the working arm 5 at a lambda distance d. The working-point end 12 corresponds to the end of the working arm 5 that is not articulated on the work carriage 4 or on the work base point 8. A work unit 17 can also be seen on the working-point end 12. The work carriage 4 is connected by means of the working arm 5 and joints that are torsionally stiff (about the y-axis) and preferably have zero clearance. Other joints of the positioning unit can be designed to have clearance. In this embodiment, the work unit 17 is designed as a holder on which a tool can be mounted. The control carriages 2, 3 and the work carriage 4 are movably arranged on a shared guiding means 13, in particular on the two guide rails 14, 15 thereof. The guiding means 13 is in turn mounted on a stand 18.

(13) Energy supply means 19, 20, 21 supply current to the control carriages 2, 3 and the work carriage 4 or current-carrying motor parts of linear motors, which parts are provided on said carriages for driving same.

(14) As a counterpart to the current-carrying motor parts, a currentless stator that extends over the entire guide rail 14 is integrated into the guide rail 14. The current-carrying motor parts and the currentless stator thus each form linear motors by means of which the control carriages 2, 3 and the work carriage 4 can be moved.

(15) Furthermore, two support arms 22, 23 that are each articulated on a base plate 16 of the work carriage 4 and on the work unit 17 can also be seen.

(16) FIG. 2 is a highly schematic representation of a positioning unit 101 that is assembled similarly to the positioning unit 1. The same reference signs as in FIG. 1 are therefore used for the elements that correspond to one another in each case.

(17) FIG. 2 in particular shows the positioning unit 101 having the support arms 22, 23 that are articulated both on the base plate 16 and on the work unit 17. The positioning unit 101 differs from the positioning unit 1 (FIG. 1) in particular in that, in the positioning unit 101, the two support arms 22, 23 are arranged below the working arm 5.

(18) The support arms 22, 23 form a parallelogram mechanism.

(19) The support arms 22, 23 also form a parallelogram mechanism together with the working arm 5.

(20) In this embodiment, the articulations are formed by joints.

(21) In addition, FIG. 2 indicates that the work unit 17 is movable in three directions x, y, z. Thus, the positioning unit 101 forms a three-axis system.

(22) In addition, the following three basic modes of movement can be combined with one another in order to move the work unit 17 in the x, y and/or z direction.

(23) A first basic mode of movement results from the control carriages 2, 3 being moved in opposite directions, while the work carriage 4 remains unmoved. This leads to a movement of the working arm 5 in the manner of a crossing gate, as a result of which the work unit 17 moves on a circular path in the plane spanned by the y and z directions.

(24) A second basic mode of movement results from the control carriages 2, 3 each being moved in the same direction relative to the work carriage 4. This allows the work unit 17 to be moved substantially—in particular at a correspondingly selected relative speed of the control carriages 2, 3 toward one another—in the plane spanned by the x and y directions.

(25) A third basic mode of movement, which leads to an exclusive movement of the work unit 17 in the x direction, results from all three carriages, i.e. the control carriages 2, 3 and the work carriage 4, being moved along the guiding means 13 at the same speed.

(26) By combining these three basic modes of movement, predefined positions within a working space 24 can therefore optionally be approached or reached by the work unit 17 or the working-point end 12.

(27) The control point 11 is spaced apart from the working-point end 12 by the lambda distance d. By selecting the position of the control point 11 along the working arm 5 or by selecting the lambda distance d, the sensitivity with which the control movements of the control carriages 2, 3 lead to movements of the work unit 17 or the working-point end 12 can be set.

(28) According to this embodiment, the working arm 5 additionally has a spindle thread (not shown in FIGS. 1 and 2 in more detail) in regions. The control point 11 has an adjusting element 25 having an internal thread, which can be moved along the spindle thread by being rotated.

(29) FIG. 3 shows an additional positioning unit 201. The positioning unit 201 is assembled largely analogously to the positioning unit 101 in FIG. 2, and therefore only the particularities of the positioning unit 201 are described in the following.

(30) The positioning unit 201 is a four-axis system. In addition to the movement of a work unit 217, which substantially corresponds to the work unit 17, in the x, y and/or z direction, the work unit 217 can also be pivoted about the z direction according to the rotational direction γ.

(31) For this purpose, the positioning unit 201 has in turn two control carriages 202, 203 and two support arms 222, 223. However, in contrast with the embodiment in FIG. 2, only one of the two support arms, in particular the support arm 223, is supported on a base plate 216 of a work carriage 204 or is articulated thereon.

(32) In contrast, the other support arm 222 is articulated on a support carriage 226. In this embodiment, the support arm 222 is articulated on both ends by means of ball-and-socket joints. The support carriage 226 is in turn movably arranged on a guiding means 213 comprising two guide rails 214, 215, in particular on the guide rail 215. The control carriages 202, 203 and the work carriage 204 are movably arranged on the shared guide rail 214.

(33) In addition, the two support arms 222, 223 are articulated on the work unit 217. The two support arms 222, 223 therefore do not form a parallelogram mechanism in this case. Rather, the support carriage 226 can be moved relative to the work carriage 204, as a result of which the work unit 217 is pivoted according to the rotational direction γ or is rotated about the z direction.

(34) FIG. 4 shows a positioning unit 301 as an additional embodiment. The positioning unit 301 is assembled as a four-axis system substantially analogously to the above-mentioned positioning unit 201. However, in contrast with the positioning unit 201, the four axes are controlled according to the rotational direction γ by a wire rope mechanism. The substantial differences between the positioning units 201 and 301 are therefore described in the following for the purpose of understanding the mode of operation of the wire rope mechanism.

(35) The positioning unit 301 has a work unit 317. The work unit 317 is articulated on a work carriage 304 by means of a pivot roller 340, a working arm 305 and a support arm 322.

(36) For this purpose, the working arm 305 is articulated on a work base point 308 that is spaced apart from the work carriage 304. The support arm 322 is articulated on a support base point 341 that is also spaced apart from the work carriage 304.

(37) The work unit 317 can be pivoted relative to the work carriage 304 according to the rotational direction γ, i.e. in the z direction, by means of the pivot roller 340. For this purpose, the pivot roller 340 is rotatably mounted between the working arm 305 and the support arm 322, and the work unit 317 is rigidly connected to the pivot roller 340.

(38) A wire rope 342 circulates or loops around the pivot roller 340 in pivot roller grooves 345. Both ends of the wire rope 342 are fixed to the pivot roller 340, the wire rope 342 being preloaded for a precise course by means of a tensioning screw arranged on the pivot roller 340.

(39) The pivot roller grooves 345 are used in particular to guide the wire rope 342 securely on the pivot roller 340, irrespective of the location or position of the work unit 317, and in particular to prevent the wire rope 342 from slipping. The number of loops of the wire rope 342 around the pivot roller 340 is selected on the basis of the desired maximum angular range of the rotation about the z axis. In this embodiment, the wire rope 342 loops once around the pivot roller 340.

(40) The wire rope 342 is further guided away from the pivot roller 340 by means of a deflection roller 331, which is indirectly arranged on the work carriage 304 so as to be rotatable, and an additional deflection roller 330 and then, from here, back to the pivot roller 340 by means of the deflection roller 331. The deflection roller 331 also has grooves for guiding the wire rope 342.

(41) The deflection roller 331 is rotatably fixed to the work base point 308 and the support base point 341.

(42) The deflection roller 330 is rigidly connected to the work carriage 304 by means of a connecting rail 344, such that, when the work carriage 304 is moved, said rail is also moved.

(43) A support carriage 326 is arranged between the deflection roller 330 and the work carriage 304 and, in particular, can be moved relative to the work carriage 304 and the deflection roller 330. The support carriage 326 has a rope fastener 343 by means of which the wire rope 342 is rigidly connected to the support carriage 326 at at least one point.

(44) By moving the support carriage 326 relative to the work carriage 304 or the deflection roller 330, the wire rope 342 is thus moved by means of the rope fastener 343, as a result of which the pivot roller 340 is in turn controlled, in particular rotated. The work unit 317 is thus pivoted according to the rotational direction γ.

(45) Therefore, a fourth axis can be controlled by the support carriage 326 also in this embodiment.

(46) According to an alternative embodiment of the invention, it is conceived that the wire rope is guided only around the rotationally fixed deflection roller 331 and the pivot roller 340 and not by means of the deflection roller 330. The work unit 317 can thus alternatively be controlled according to a parallelogram mechanism in an easy and inexpensive way.

(47) The schematic representation in FIG. 5 shows an alternative embodiment of two support arms as flexible tension elements by means of which a parallelogram mechanism is formed.

(48) Shown in a side view is a work carriage 404 that is connected to a work unit 417 by means of two spring steel strips 427, 428. The spring steel strips 427, 428 are made of resilient spring steel and form flexible tension elements. It can also be seen in FIG. 5 that a working arm 405 (that can be subjected to compression loading) is articulated on the work unit 417 and on the work carriage 404.

(49) If the work unit 417 is moved relative to the work carriage 404 in the image plane of FIG. 5, the spring steel strips 427, 428 deform but maintain their tensile effect. A parallelogram mechanism is thus formed, allowing joints for the spring steel strips 427, 428 to be dispensed with.

(50) FIG. 6 is a schematic representation of a design and mode of operation of an impulse decoupling unit 537 of a positioning unit.

(51) A guiding means 513 can first be seen on which a carriage, in particular a control carriage 502, is movably arranged. A linear motor is provided for driving the control carriage 502. The linear motor is formed by a currentless stator 532 that has magnetic strips having regularly arranged magnetic regions of alternating directions of polarization, and a current-carrying motor part 535. The stator 532 and the current-carrying motor part 535 slide along one another and together form a linear motor.

(52) The motor part 535 is supplied with current by an energy supply means 536.

(53) The stator 532 is slidably mounted on the guiding means 513.

(54) When the control carriage 502 accelerates, it is supported on the stator 532 in a frictional connection. The stator 532 is accelerated counter to the direction of acceleration of the control carriage 502 by means of the recoil impulse. Additional masses 533, 534 are provided in order to keep the absolute deflections of the stator 532 low. Said masses are substantially greater than, in particular a multiple of, the mass of the control carriage 502. Therefore, owing to the mobility of the stator 532, recoil impulses of the control carriage 502 or the masses arranged thereon accelerate the stator 532 along with the masses 533, 534 thereof. A stand (not shown in more detail in FIG. 6 for the sake of simplicity) supporting the positioning unit is thus relieved of the recoil impulses.

(55) The control carriage 502 is shown by way of example for additional carriages, in particular for an additional control carriage and for a work carriage that are arranged so as to be movable along the stator 532 analogously to the carriage 502. Recoil impulses from a plurality of carriages can therefore be decoupled or respectively absorbed by the arrangement shown in FIG. 6.

(56) In an alternative embodiment, the positioning unit additionally has a position measuring system for detecting the position of the stator 532. The position of the stator 532 is continuously detected or respectively monitored by said position measuring system, such that the current-carrying motor part 535 can be controlled in a manner aligned with the corresponding position of the magnetic strip or the position of the magnetic regions and the respective directions of polarization thereof.

(57) FIG. 7 shows an embodiment of a weight compensation unit 638.

(58) A work unit 617 can be seen in a side view. The mass of the work unit 617 causes a weight force that is directed in the direction of gravity g. Said weight force should be compensated for in order to achieve a highly dynamic positioning system and relieve the strain on the respective drives.

(59) The mode of operation of the compensation unit 638 is explained by way of example on the basis of two support arms 622, 623 that form a parallelogram mechanism. It can be seen that a compensation element 639 is arranged between the support arms 622, 623. In this embodiment, the compensation element 639 is designed as a compression spring.

(60) In an alternative embodiment, the compensation element 639 is formed by spiral springs in the articulations. In an additional alternative embodiment, the compensation element 639 is designed as a pneumatic piston.

(61) If the work unit 617 is therefore moved along the image plane, i.e. in or counter to the direction of gravity g, and therefore out of a zero position, the compensation element 639 is tensioned. The compensation element 639 therefore works against a deflection of the work unit 617 out of the zero position thereof in each case. Preloading the compensation element 639 in particular allows the work unit 617 to be located in the region of the zero position thereof when in the idle state. In the case of the alternative embodiment as a pneumatic piston, a balancing force that is adapted to the mass to be compensated for is hydraulically produced by means of pressure regulation.

(62) The weight of the work unit 617 is thus at least partially compensated for by the compensation element 639. In addition, it can therefore also be ensured that the work unit 617 is moved back at least toward the zero position thereof in an emergency-stop situation.

LIST OF REFERENCE SIGNS

(63) 1, 101, 201, 301 positioning unit 2, 3, 202, 203, 502 control carriage 4, 204, 304, 404 work carriage 5, 305, 405 working arm 6, 7 control arm 8, 308 work base point 9, 10 control base point 11 control point 12 working-point end 13, 213, 513 guiding means 14, 15, 214, 215 guide rail 16, 216 base plate 17, 217, 317, 417, 617 work unit 18 stand 19, 20, 21, 536 energy supply means 22, 23, 222, 223, 322, 622, 623 support arm 24 working space 25 adjusting element 226, 326 support carriage 427, 428 spring steel strip 330, 331 deflection roller 532 stator 533, 534 mass 535 motor part 537 impulse decoupling unit 638 weight compensation unit 639 compensation element 340 pivot roller 341 support base point 342 wire rope 343 rope fastener 344 connecting rail 345 pivot roller groove d lambda distance x, y, z directions γ rotational direction g direction of gravity