Abstract
The invention relates to a coordinate-measuring machine for determining at least one spatial coordinate of a measurement point on a measuring object, comprising a base, a carrier comprising at least one carrier segment, a proximal end of the carrier being mounted pivotably about a base axis in the base, a measuring probe being arranged on a distal end of the carrier, and an angle measuring system for determining pivot angles of the at least one carrier segment, and/or rotation angles of the measuring probe, wherein at least one belt drive comprising a base pulley being arranged in the base, at least one follower pulley being arranged on at least one carrier segment, and at least one belt binding the rotatory behavior of said pulleys.
Claims
1. A coordinate-measuring machine having a Selective Compliance Robot Arm (SCARA)-structure, configured for determining at least one spatial coordinate of a measurement point on a measuring object, coordinate-measuring machine comprising: a base; a carrier comprising more than one carrier segment, which are horizontally pivotable relative to each other about vertical segment axes, a proximal end of the carrier being mounted pivotably about a vertical base axis in the base; a measuring probe being arranged on a distal end of the carrier; an angle measuring system for determining: pivot angles of the carrier segments, at least one belt drive comprising: a base pulley being arranged in the base, wherein the axis of the base pulley coincides with the base axis, at least one follower pulley being arranged on at least one of the carrier segments, wherein one follower pulley is fixedly connected to one of the carrier segments, at least one belt binding the rotatory behaviour of the base pulley and the at least one follower pulley, at least one motor arranged in the base and driving the base pulley for a controlled positioning of the measuring probe or one of the carrier segments, and a control unit for controlling the motor.
2. The coordinate-measuring machine according to claim 1, wherein: the measuring probe being fixedly connected with a follower pulley arranged on the distal end of the carrier, wherein the measuring probe is rotatably mounted in the distal end of the carrier.
3. The coordinate-measuring machine according to claim 1, wherein: one of the at least one follower pulley is rotatably mounted in the distal end of the carrier.
4. The coordinate-measuring machine according to claim 1, wherein: the base pulley being a fixed base pulley which is fixed and prevented from rotating, and the at least one follower pulley being a rotatable follower pulley which is rotatable relative to the carrier segment it is arranged on.
5. The coordinate-measuring machine according to claim 1, wherein: the base pulley being a driven base pulley which is driven by one of the at least one motor.
6. The coordinate-measuring machine according to claim 1, wherein: the at least one follower pulley being a rotatable follower pulley which is rotatable relative to the carrier segment it is arranged on.
7. The coordinate-measuring machine according to claim 1, wherein: at least one follower pulley being a fixed follower pulley which is fixedly attached to the carrier segment it is arranged on.
8. The coordinate-measuring machine according to claim 1, wherein: one of the at least one belt being wrapped around one of the at least one base pulley and at least one follower pulley and thereby binding the rotatory behaviour of the base pulley and the at least one follower pulley.
9. The coordinate-measuring machine according to claim 1, wherein: one of the at least one belt being wrapped around at least two follower pulleys and thereby binding the rotatory behaviour of the at least two follower pulleys.
10. The coordinate-measuring machine according to claim 1, wherein: the carrier is vertically adjustable by a lift positioned in the base.
11. The coordinate measuring machine according to claim 1, wherein: each of the at least one follower pulley is mounted on one of the carrier segments such that the axis of the follower pulley coincides with a segment axis.
12. The coordinate measuring machine according to claim 1, wherein: one of the at least one follower pulley having an axis angled by 90 degrees relative to the axis of a pulley it is bound to via one of the at least one belt.
13. The coordinate-measuring machine according to claim 1, wherein: the measuring probe is vertically adjustable by one of the at least one belt drive, wherein the axis of a distal follower pulley is angled relative to the base pulley, and wherein the distal follower pulley has a pinion driving a gear rack, to which the measuring probe is attached.
14. The coordinate-measuring machine according to claim 1, wherein: the measuring probe is vertically adjustable by one of the at least one belt drive, wherein the axis of a distal follower pulley is angled 90 degrees relative to the base pulley, and wherein the distal follower pulley has a pinion driving a gear rack, to which the measuring probe is attached.
15. The coordinate-measuring machine according to claim 1, wherein: the measuring probe is vertically adjustable by one of the at least one belt drive comprising at least two follower pulleys, that are entangled by a distal belt and the axes of which are angled relative to the base pulley, wherein the measuring probe is linked to the distal belt, which therewith provides and up and down movement.
16. The coordinate measuring machine according to claim 1, wherein: the measuring probe is vertically adjustable by one of the at least one belt drive comprising at least two follower pulleys, that are entangled by a distal belt and the axes of which are angled by 90 degrees relative to the base pulley, wherein the measuring probe is linked to the distal belt, which therewith provides and up and down movement.
17. The coordinate measuring machine according to claim 1, wherein: the measuring probe being mounted on a holder such that it is pivotable about a horizontal axis by a belt drive comprising at least two follower pulleys, the axes of which are angled relative to each other, and relative to the base pulley.
Description
BRIEF DESCRIPTION OF THE FIGURES
(1) The method and the device according to the invention are described or explained in more detail below, purely by way of example, with reference to working examples shown schematically in the drawings. Specifically,
(2) FIG. 1a shows an embodiment of a coordinate measuring machine (CMM) according to the invention;
(3) FIG. 1b shows the movabilities of the CMM from FIG. 1a in a top view;
(4) FIG. 1c is a side view of the CMM from FIG. 1a;
(5) FIG. 2a shows the movabilities of a further embodiment of a CMM according to the invention in a top view;
(6) FIG. 2b is a side view of the CMM from FIG. 2a;
(7) FIG. 3a shows the movabilities of a further embodiment of a CMM according to the invention in a top view;
(8) FIG. 3b is a side view of the CMM from FIG. 3a;
(9) FIG. 4 is a synoptic table showing the three principles of manipulating the probe/carrier with means of a belt drive according to the invention;
(10) FIG. 5a shows a further embodiment of a coordinate measuring machine (CMM) according to the invention;
(11) FIG. 5b shows the movabilities of the CMM from FIG. 5a in a top view;
(12) FIG. 5c is a side view of the CMM from FIG. 5a;
(13) FIG. 6a shows the movabilities of a further embodiment of a CMM according to the invention in a top view;
(14) FIG. 6b is a side view of the CMM from FIG. 6a;
(15) FIG. 7a shows the movabilities of a further embodiment of a CMM according to the invention in a top view;
(16) FIG. 7b is a side view of the CMM from FIG. 7a;
(17) FIG. 8a shows the movabilities of a further embodiment of a CMM according to the invention in a top view;
(18) FIG. 8b is a side view of the CMM from FIG. 8a;
(19) FIG. 9a shows the movabilities of a further embodiment of a CMM according to the invention in a top view;
(20) FIG. 9b is a side view of the CMM from FIG. 9a;
(21) FIG. 10a shows the movabilities of a further embodiment of a CMM according to the invention in a top view;
(22) FIG. 10b shows the movabilities of a further embodiment of a CMM according to the invention in a top view;
(23) FIG. 11a shows a further embodiment of a CMM according to the invention in a top view;
(24) FIG. 11b is a side view of the CMM from FIG. 11a;
(25) FIG. 11c is a front view of the CMM from FIG. 11a;
(26) FIG. 12a shows a further embodiment of a CMM according to the invention in a top view;
(27) FIG. 12b is a side view of the CMM from FIG. 12a;
(28) FIG. 12c is a front view of the CMM from FIG. 12a;
(29) FIG. 13 is a side view of a further embodiment of a CMM according to the invention, providing a vertical measuring probe adjustability;
(30) FIG. 14 is a side view of a further embodiment of a CMM according to the invention, providing a vertical measuring probe adjustability;
(31) FIG. 15 is a side view of a further embodiment of a CMM according to the invention, providing a tilt-turn measuring probe head;
DETAILED DESCRIPTION
(32) FIGS. 1a, 1b and 1c show an embodiment of a coordinate measuring machine (CMM) 1 according to the invention. The CMM comprises a base 2, a carrier 3 comprising at least one carrier segment 3, a proximal end of the carrier being mounted pivotably about a base axis 8 in the base 2, a measuring probe 4 being arranged on a distal end of the carrier, and an angle measuring system A for determining pivot angles of the at least one carrier segment. Furthermore, the CMM has a belt drive comprising a base pulley 5.sup.f of which the axis coincides with the base axis 8, a follower pulley 6 being arranged on the carrier segment 3, and at least one belt 7 binding the rotatory behaviour of said pulleys.
(33) FIG. 1a shows an embodiment of a CMM 1 according to the invention in a three dimensional perspective and with the carrier 3 only having one carrier arm segment 3. The carrier segment 3 has a base pulley, which in this figure is hidden in the base 2, and a follower pulley 6, which is connected with a measuring probe 4 (internally with regard to shown parts), so that a rotation of the follower pulley 6 is directly transmitted to the measuring probe 4. The follower pulley 6 and the base pulley are embraced by a cable 7, so that this arrangement works like a belt drive. However, as FIGS. 1b and 1c will show, the base pulley is not driven and, hence, will not actively transmit any rotation onto follower pulley 6.
(34) FIG. 1b shows the CMM 1 from FIG. 1a from a top view perspective. The circular arrows connote the respective pivoting/rotating which is possible with this embodiment. The solid line means, an active pivoting of the carrier segment 3 (by a motor not shown) around the base axis 8 is possible, and the dashed line means that the follower pulley (and therewith also the measuring probe) is passively rotating in the opposite direction of the carrier pivoting relative to the carrier segment. Base pulley 5.sup.f, in this embodiment, is a fixed base pulley 5.sup.f and is therefore prevented from rotating relative to the base. Cable 7 now directly links the fixed base pulley 5.sup.f with the follower pulley 6 and therefore restricts follower pulley 6 from rotating relative to the base, when the carrier 3 is pivoted about the base axis 8. This prevention from rotation, at the same time, means a rotation of follower pulley 6 relative to the carrier segment 3. This effect ensures a constant alignment of the measuring probe, no matter what the orientation of the carrier.
(35) FIG. 1c shows the CMM 1 from FIG. 1b from a side view perspective. This perspective further reveals the motor M, which directly drives the carrier segment 3, and a lift, by which the whole measuring arm arrangement can be adjusted in height. As depictured, fixed base pulley 5.sup.f can be attached to the lift by a crane in order to follow the height adjustment. Also shown is the motor M and a control unit C for controlling the motor M that is arranged in the base 2, the motor m driving the fixed base pulley 5.sup.f for a controlled positioning of the measuring probe 4 or a carrier segment 3.
(36) FIGS. 2a and 2b show a further embodiment of a coordinate measuring machine (CMM) 1 according to the invention. This embodiment differs from the embodiment shown in FIGS. 1a-c in that the CMM comprises two belt drives.
(37) The first belt drive (5.sup.f,6,7) ensures the constant alignment of measuring probe 4 according to the embodiment shown in FIGS. 1a-c. Follower pulley 6 is mounted in the carrier segment 3 such that is can rotate freely relative to it.
(38) The second belt drive (5.sup.d,6,7) works independent from the first belt drive. The carrier segment 3, herewith, is driven in an unconventional way. A motor M drives the driven base pulley 5.sup.d, but since follower pulley 6 is a fixed follower pulley restricted from rotating relative to carrier segment 3, driven base pulley 5.sup.d is also bound to the rotation of carrier segment 3 and also cannot rotate relative to it. The momentum causing the carrier segment 3 to pivot is generated at the follower pulley 6 and the tight side of the belt pulling on its perimeter surface.
(39) FIGS. 3a and 3b show a further embodiment of a coordinate measuring machine (CMM) 1 according to the invention. This embodiment differs from the embodiment shown in FIGS. 1a-c in that the follower pulley is actively and independently controllable via a motor m. In this embodiment, base pulley 5.sup.d is a driven base pulley 5.sup.d and the follower pulley 6 is a rotatable follower pulley. With motor m, therefore, the rotational behaviour of measuring probe 4 is controlled, independent from the movement or position of the carrier. Carrier segment 3 is pivotable with motor M. If motor m is blocked and prevents base pulley 5.sup.d from rotating, the features of guiding the fixed alignment of the probe 4 according to the fixed base pulley, as shown in FIGS. 1a-c, are given.
(40) FIG. 4 provides an overview of the three purposes of manipulating the probe/carrier with means of a belt drive according to the invention and how each manipulation is forwarded on a multi-segment carrier.
(41) The base pulley (input) is considered to determine the follower pulley's conduct (output). Optionally, for forwarding (passing on) the input to the output, a follower pulley is provided, which preferentially can be a twin-pulley, for each additional carrier segment. In this case, input and output are not positioned on the same carrier segment and therefore need a redirection at the respective joint(s).
(42) Probe guiding: According to the mechanism described with FIGS. 1a, 1b and 1c, probe guiding is the retention of the measuring probe's alignment, even if the carrier segment(s) are pivoted, with help of a fixed base pulley. Output (follower pulley), then, must be a rotatable follower pulley in order to follow (keep) a fixed alignment relative to a base reference system. In case the carrier comprises more than one segment, passing on is provided by a set of two pulleys, wherein the first pulley (forwarding follower pulley) is paired with the base pulley and the second pulley (fixed follower pulley) is paired with the follower pulley, the latter being connected to the probe. Preferably, said pairs are each entangled by a belt, and thereby bound to each other. The twin-pulley is a fixed arrangement, so that the forwarding follower pulley and the fixed follower pulley cannot rotate relative to each other. Furthermore, the twin-pulley is freely rotatably mounted in the carrier so that it can easily comply with the base pulley's alignment. As the twin-pulley is now following strictly the fixed base pulley's alignment, the fixed follower pulley earns its byname fixed, as it has the same characteristics to the rotatable follower pulley, as has the fixed base pulley to the forwarding follower pulley. By this arrangement, a probe head always keeps a stationary alignment (with respect to the base), no matter which orientation the carrier segment(s) are adopting.
(43) Probe/carrier motorizing: According to the mechanism described with FIGS. 3a and 3b, probe/carrier motorizing addresses the active and independent controlling of the measuring probe or a carrier segment with a belt drive comprising at least a driven base pulley (input) and a rotatable follower pulley (output). In case the carrier comprises more than one segment, passing on is provided by a set of two pulleys, wherein the first pulley (forwarding follower pulley) is paired with the base pulley and the second pulley (driven follower pulley) is paired with the follower pulley, the latter being connected to the probe or to a further carrier segment. The driven follower pulley earns its name as it inherits the features of the base pulley and therewith just forwards the rotation to the rotatable follower pulley.
(44) Carrier pivoting: Above described (i) as well as the propulsion of the CMM in FIGS. 2a and 2b are a special case of carrier pivoting, in which the output is a fixed follower pulley, which is fixed relative to the carrier segment which it is arranged on. The driven base pulley applies a momentum on the distal carrier segment with attempting to move the belt according to the base pulley. Such movement, however, is only possible, when the carrier segment pivots accordingly. Again, this principle is extendable by a twin-pulley as it was described under probe/carrier motorizing.
(45) The three shown principles are combinable so that multiple belt drives provide the desired movabilities (probe, single carrier segments). The following figures demonstrate isolated embodiments which are likewise combinable.
(46) FIGS. 5a, 5b and 5c show an embodiment of a CMM according to the probe guiding principle in FIG. 4, the CMM's carrier 3 comprising three carrier segments 3, 3, 3, which are pivotable relative to each other about vertical segment axes 9, 9, 9. Further, it comprises a fixed base pulley 5.sup.f, four follower pulleys 6, 6, 6, 6 for passing on the fixed alignment and a rotatable follower pulley 6, to which the measuring probe 4 is coupled.
(47) The dashed arrow around follower pulley 6 in FIG. 5b implies its linkage to fixed base pulley 5.sup.f and that it will keep its alignment in every possible carrier segment position.
(48) FIG. 5c shows the CMM in a side view. The belt drive comprises three parts: fixed base pulley 5.sup.f and forwarding follower pulley 6 being embraced by cable 7, fixed follower pulley 6 and forwarding follower pulley 6 being embraced by cable 7, and fixed follower pulley 6 and rotatable follower pulley 6 being embraced by cable 7.
(49) Pulleys 6 and 6 on the one hand, as well as pulleys 6 and 6 on the other hand, are linked fixedly, so that they cannot rotate relative to each other. However, they are rotatable around the vertical segment axes 9, 9 and 9, respectively, and are accordingly mounted in the carrier segments 3, 3 and 3, respectively.
(50) A drive for the single carrier segments is not yet provided with this embodiment. Drives for the single carrier segments shall be described in the following figures.
(51) FIGS. 6a and 6b show an embodiment of the belt drive equipped CMM according to the invention, wherein a second (and, concomitant with it, a distal) carrier segment is driven by a motor m and by means of a driven base pulley 5.sup.d and a rotatable follower pulley 6, according to the probe/carrier motorizing principle disclosed in FIG. 4, while said pulleys are entangled by belt 7. The solid line arrow indicates the turnability of carrier segment 3 around the segment axis 9. Rotatable follower pulley 6 is rotatable with regard to carrier segment 3, however it is fixedly connected with carrier segment 3, so carrier segment 3 exactly follows the rotation of driven base pulley 5.sup.d.
(52) By the same principle, FIGS. 7a and 7b show the motorization of carrier segment 3, which is attached to follower pulley 6. The set of pulleys, comprising driven follower pulley 6 and forwarding follower pulley 6 (according FIG. 4's terminology), passes on the rotation of driven base pulley 5.sup.d to rotatable follower pulley 6. Yet again, the solid arrow indicates the function of this belt drive.
(53) FIGS. 8a and 8b show a general alternative for having multiple pulleys at one axis for forwarding the pulley's rotation. In this embodiment, which is (due to the small rotation angle range) especially suitable for the probe guiding concept according to FIG. 4, the belt drive only comprises one belt (or cable, etc.) that is wrapped around the two forwarding pulleys in order to follow the track of the carrier arm segments. Both slack side and tight side of the belt are entangling the forwarder pulleys by 360. To avoid high friction, the belt can follow spiral grooves applied on the pulleys' perimeters.
(54) FIGS. 9a and 9b show another embodiment of the CMM according to the invention. Demonstrated is a double arm structure of the carrier while being designed to be equipped with any of the guiding/motorizing/pivoting arrangements as described above.
(55) A drive for the double arm carrier is not yet provided with this embodiment. Applicable drives shall be described in the following figures.
(56) FIGS. 10a and 10b each show a drive for the first and the second double arm while using the principle described under FIG. 6. Because both double arms are linked as shown, the drive demonstrated in FIG. 10b realizes a linear movement of the distal carrier end as indicated by the solid arrow line.
(57) FIGS. 11a, 11b and 11c show another embodiment of the CMM according to the invention. Demonstrated is a redirection of the cable drive in order to provide the measuring probe 4 with a rotation-functionality with a horizontal axis 10. In FIG. 11c, further pulleys are not shown to simplify matters.
(58) If circumstances require, like in this example, it might be necessary to have two axes redirections to provide said rotatability for the measuring probe. Alternatively or additionally, a gear transmission can fulfil the same axis tilting.
(59) At first, follower pulley 6 passes rotation on to follower pulley 6 of which the rotation axis 10 is horizontal and tilted by 90 with respect to the vertical segment axis 9. Follower pulley 6 fixedly connected with follower pulley 6 then passes rotation on to follower pulley 6 of which the rotation axis 10 is horizontal and tilted by 90 with respect to the horizontal axis 10. Pulley 6 directly drives measuring probe 4, which is mounted in a holder 11, the holder being attached to the carrier.
(60) FIGS. 12a, 12b and 12c show another embodiment of the CMM according to the invention. Demonstrated is a redirection of the cable drive in order to provide the measuring probe 4 with a rotation-functionality around a horizontal axis 10, while using only a single cable 7.
(61) In this example, the deflection is provided in a different way than in FIGS. 11a-c. Each tight side and slack side of belt 7 lead to a horizontally rotatable (about axis 10) pulley (6 and 6) by which belt 7 then is redirected downwards to pulley 6. No matter how base pulley 5.sup.d is rotating, pulleys 6 and 6 will always rotate in an opposite direction. Follower pulley 6 is rotatably mounted in carrier 11 and therewith connected with carrier segment 3. Pulley 6 provides rotation about horizontal axis 10 for measuring probe 4.
(62) FIGS. 13 and 14 show two alternative possibilities for providing a vertical hoist axis in the system, in particular, providing it for the measuring probe in order to reach surfaces in a bore hole. Both examples are also equipped with a direct motor M to drive the carrier 3 (which only has one carrier element 3), and a motor m for adjusting the height of the measuring probe 4. The hoist axis is not necessarily a substitute for the lift, but can also be used additionally.
(63) In FIG. 13, follower pulley 6 redirects rotation to pulley 6 as introduced in FIGS. 11a-c, and height adjustment is realized by holder 12 being mounted on holder 11 while being directly carried upwards and downwards with means of cable 7. For this purpose, one side of the cable 7 and holder 12 can be linked and the other side of the cable 7 just passes through holder 12.
(64) FIG. 14 shows an alternative for the probe hoist axis, wherein rotation of the follower pulley 6 is directly converted into a translation via pinion 13 and gear rack 14. The gear rack 14 is mounted in the holder 11, and pinion 13 is fixedly attached to pulley 6 and shares the rotation axis of the pulley 6. Furthermore, the redirection of the pulley axes takes place already between driven base pulley 5.sup.d and follower pulley 6.
(65) FIG. 15 shows an embodiment of the inventive CMM comprising a measuring probe head which provides two further degrees of freedom independently (tilt-turn functionality). Measuring probe 4 can be rotated about a vertical axis 15 and a horizontal axis 15 by means of light weight micro motors (not shown). Pulley 6 is controlled by a motor m and provides rotation of carrier segment 3 around axis 9, and carrier segment 3 is provided rotation by motor M. The measuring probe head is standard equipment and can be modularly attached to carrier 3 (e.g. at a dock), whereby connectivity regarding control and power supply is provided at the docking mount.
(66) All shown embodiments may comprise an angle measuring system and/or a linear length measuring system for every carrier segment and/or measuring probe that is adjustable. All of the above described embodiments whatsoever are combinable with each other by adding the needed components and arrangement into the coordinate measuring machine.
