DE3508143A1 - Two-coordinate length measuring device - Google Patents

Abstract

The two-coordinate length measuring device is used to measure tools when presetting numerically controlled machine tools or to measure workpieces. It comprises a table (1) having at least one receptacle (57, 71) for a tool (61) or a workpiece. It has further two linear guiding units (7, 17), of which each has two guide elements (13, 19, 21), which can move in a linear fashion relative to one another, and a length measuring device (27) which detects the relative position of the two guide elements and generates an information signal representing the relative position. One of the guide elements of a first (7) of the two linear guiding units (7, 17) is firmly connected to the table (1). One of the guide elements (21) of the second linear guiding unit (17) supports a probe element (49), while the other guide element (19) of the second linear guiding unit (17) is firmly held on the other guide element (13) of the first linear guiding unit (7) in such a way that the probe element (49) can be displaced relative to the table (1) in conjunction with a relative displacement of the guide elements in the displacement directions of the two linear guiding units (7, 17). The probe element (49) is constructed as a movable probe on a feeler length measuring device (47) and can for its part be displaced linearly relative to the guide element (21) of the second linear guiding unit (17) for the purpose of length measurement. The feeler length measuring device (47) is ... Original abstract incomplete. <IMAGE>

Description

description

The invention relates to a two-coordinate length measuring device, comprising a table with at least one holder for a tool or workpiece, two Linear guide units, each of which is two linearly displaceable relative to one another Guide elements and one that detects the relative position of the two guide elements and a length measuring device generating the information signal representing the relative position having one of the guide elements of a first of the two linear guide units is firmly connected to the table and wherein one of the guide elements of the second Linear guide unit carries a feeler element and the other guide element of the second Linear guide unit fixed to the other guide element of the first linear guide unit is held in such a way that the tactile organ with relative displacement of the guide elements in the directions of displacement of the two linear guide units relative to the table is movable.

A two-coordinate length measuring device of this type is disclosed in DE-PS 25 12 787 known. It allows the tool dimensions to be determined in a numerically controlled manner Machine tools independent of the machine tool. The ones determined on the tool Dimensions are set when the machine tool is preset in its numerical control entered and then automatically taken into account.

The known two-coordinate length measuring device includes a perpendicular Guide column protruding from the table on which a pneumatically supported slide Plain bearing is slidably guided. The slide is perpendicular to the direction of displacement the guide column is guided displaceably by an arm, which has a touch surface piece at its free end wearing. The position of the slide relative to the guide column and the position of the Arms relative to the carriage is each detected with a length measuring device, the an information signal corresponding to the relative position to the numerical control the machine tool delivers. Each of the length measuring devices comprises a sensor, which scans a scale attached to the guide column or the slide. The tool is held in a table-fixed tool holder for the measurement.

In the known length measuring device, the touch surface piece is not with defined tracing force pressed against the tool. If used carelessly, the tool damage the touch surfaces and the measuring accuracy suffers. In particular For this reason, the known length measuring device cannot be used for control measurement of the Workpieces produced on the machine tool are used.

It is the object of the invention to provide the known two-coordinate length measuring device to improve in a structurally simple manner so that in both coordinate directions Length measurements can be carried out with a predetermined stylus force, so that the Length measuring device suitable for measuring tools as well as workpieces is.

According to the invention, this object is described in greater detail on the basis of the above explained two-coordinate length measuring device solved in that the tactile organ as movable probe of a length probe is designed and for length measurement in turn relative to the guide element holding the length probe second linear guide unit is linearly displaceable and that the length measuring device around one perpendicular to the directions of displacement of the two linear guide units Rotation axis rotatable on the one guide element of the second linear guide unit held and by means of an index locking device with the displacement directions of the linear guide units can be locked in parallel shifting direction of the button is.

Here and in the following, under two perpendicular directions or Axes are understood to mean that these are in a direction or axis to the other vertical plane. The length measuring device ensures a predetermined tactile force Size and facilitates the handling of the two-coordinate measuring device because the Linear guide units only approximately when scanning the tool or workpiece need to be aligned. Misalignments can be detected by the length measuring device detected positional errors are corrected. The length measuring device can it is a mechanical tactile clock, the measured value of which corresponds to that of the length measuring devices of the linear guide units is added with the correct sign. In preferred refinements, however, are a tactile measuring device which is similar the length measuring devices of the linear guide units electrical information signals for the misalignment, so that an automatic correction of the length measuring devices determined measured values is possible.

The length measuring device is common for both coordinate directions exploited. This eliminates the need for a second length measuring device. Furthermore are the measurement errors caused by the length measuring device for both coordinate directions same.

The touch points are in the same for both coordinate directions Plane parallel to the directions of displacement of the two linear guide units, with which no touch point misalignments occur and the probe in both coordinate directions has the same dimension from the axis of rotation.

The length measuring devices of the linear guide units and the length measuring device can be conventional. It is expedient to use measuring devices whose zero point is electrically adjustable at will.

In a preferred embodiment, the linear guide units are essentially the same and each comprise an elongated guide rail and a slide displaceable along the guide rail. The guide rail the first linear guide unit preferably runs parallel to the table so that they for example, by being held at both ends on the table, by the table is stiffened.

The guide rail of the second linear guide unit is with a End held on the carriage of the first linear guide unit and extends vertically to the table. In this way, a comparatively large measuring range can be used reach both coordinate directions.

The length measuring device is expediently at the free end of a arm protruding freely across the directions of displacement of the two guide rails held. around the transverse dimensions of the tool or

Workpiece to be able to take into account.

In a preferred embodiment the length measuring device is a tactile measuring device on a rotatable, but movable in the direction of the axis of rotation on the arm Head held. The head carries an axle which is mounted in a bearing flange of the arm and biases the head against the bearing flange via a spring. The spring force is to simplify the construction at the same time to generate the locking forces of the Index locking device used. The index locking device comprises this axially protruding lugs or complementary recesses, which are also used for control a control switch can be used, which is the rotational position of the head and thus the control signal representing the measuring direction is generated.

In a preferred embodiment, the table carries both one Rotary mounting head with a mounting cone for steep taper shank tools as well one perpendicular to the directions of displacement of the linear management units running, Stop shoulder protruding above the table surface for aligning the one to be measured Work pieces. The rotary recording head is expediently by means of an index locking device fixable in predetermined rotational positions relative to the table in order to move the tool in to be able to measure predetermined rotational positions. For turning the rotary pick-up head this is expediently provided with a handwheel, which is also used for Loosen or close one of the steep taper shank in the receiving cone Jig is used.

In order to increase the range of use of the measuring device even further, is a scriber is also attached to the head carrying the length measuring device.

The length measuring devices can be monitored in this way Draw precision sketches.

The linear guide units are high-precision sliding guides, which are comparatively smooth-running despite the precision guidance properties have to be able to probe more or less smoothly. A linear guide unit with these properties, which are not only found in the measuring device described above, but can also be used for guidance purposes of other types includes a Guide rail, one on each of two opposite longitudinal outer sides Pair of guide surfaces formed by a longitudinal groove in the longitudinal outer side with one another to be pointed and to the respective other pair of guide surfaces towards each other in a V-shape Has to run guide surfaces. The one that can be moved along the guide rail On both sides of the guide rail, the slide carries one of several into the Longitudinal groove engaging, rotatable rollers existing roller set, the roles of which Carriage at at least three spaced apart locations along the Support the pair of guide surfaces so that they can roll on this. The roles of one of the two Roller sets are mounted on bearings fixed to the slide, while the rollers of the other Roll set are stored on a fitting piece, which on slide fixed fitting surfaces slidable to the longitudinal groove assigned to it, but guided transversely to it is. Between the fitting piece and the slide there is a fitting piece on the one assigned to it Longitudinal groove to be prestressed spring clamped. The guide surfaces are each protected within the longitudinal groove. The rollers guide the carriage on the guide rail so that it does not tip over, the spring compensating for the play between the roles.

The fitting is preferably on two in the longitudinal direction of the guide rail at a distance from each other, cylindrical dowel pins of the slide displaceable out, since such dowel pins can be precisely manufactured and used. To adjust the spring force, the spring is preferably via an adjusting screw supported on the slide. The spring is expediently to a disc spring or a disc spring assembly to generate sufficiently large spring forces to be able to.

In the following, an embodiment of the invention will be based on Drawings are explained in more detail.

1 shows a side view of a tool for measuring tools and workpieces suitable two-coordinate length measuring device; Fig. 2 is a plan view on the length measuring device; FIG. 3 is a sectional view of a device used in the measuring device of FIG. 1 usable linear guide unit, seen across the direction of displacement along a line 111-111 in Fig. 5; 4 is a sectional view of the linear guide unit seen transversely to the displacement direction along a line IV-IV in Fig. 5 and Fig. 5 is a partial side view of the linear guide unit.

The two-coordinate length measuring device allows the measurement of steep-taper tools for presetting numerically controlled machine tools as well as measuring of workpieces produced on these machines, for example. It includes one essentially rectangular, stable table 1 with a ground, flat one upper surface 3, which stands on adjustable, vibration-damping rubber feet 5. A first linear guide unit extends along one of the two longitudinal edges of the table 1 7. The linear guide unit 7 comprises a flange 9 at both ends fixed to the table 1 guide rail 11, along which a carriage 13 by means of a Friction wheel drive 15 is displaceable. Perpendicular to the direction of displacement of the linear guide unit 7 extends a second linear guide unit 17. The linear guide unit 17 comprises a guide rail 19 extending perpendicular to the table plane 3, along which a slide 21 can be displaced by means of a friction wheel drive 23. the One end of the guide rail 19 is attached to the carriage 13 and is stationary otherwise free-standing.

The guide rail 11 of the linear guide unit 7 carries a measuring scale 25, by a measuring head (not shown in more detail in FIGS. 1 and 2) of a length measuring device is scanned. The length measuring device is conventional and provides one of the relative position between the carriage 13 and the guide rail 11 directly proportional signal, which is displayed in units of length on a display device and / or directly for presetting the numerically controlled machine tool is delivered. The zero point of the length measuring device can be done electrically can be given arbitrarily. The linear guide unit is in a corresponding manner constructed, with a measuring head held on the carriage 21 and one on the guide rail 19 attached measuring scale 27 scans. The guide rails 11, 19 are on both sides the carriage 13, 21 by bellows 29, 31 from dirt and damage protected.

The slide 21 is essentially perpendicular to the directions of displacement of the linear guide units 7, 17 an arm 33 extending over the table surface 3 in a self-supporting manner away. In a bearing flange 35 at the free end of the arm 33, a head 37 is around a axis of rotation perpendicular to the directions of displacement of the linear guide units 7, 17 rotatable but axially displaceable.

For this purpose, the head 37 carries an axis penetrating the bearing flange 35 39 and is of a helical compression spring 41 surrounding the axis 39 against the The end face of the bearing flange 35 remote from the slide is tensioned. The helical compression spring 41 is for this purpose between an abutment head attached to the free end of the axis 39 43 and the bearing flange 35 clamped.

The head 37 is removably attached by means of a knurled screw 45 a length measuring device 47, the probe 49 of which is perpendicular to the axis of rotation of the head 37 is resiliently displaceable. The head 37 is by means of an index locking device, which from at least one axially protruding nose 51, for example the head 37 and there is a plurality of complementary recesses 53, in predetermined rotational positions lockable, in which the direction of displacement of the button 49 is parallel to the direction of displacement the linear guide unit 7 or the linear guide unit 17 runs. The springy one Button 49 of the tactile measuring device 47 equates to positional errors of the carriage 13. 21 at Probing the tool or workpiece with an essentially constant tracing force the end. The position error is displayed and with the measurement result of the linear guide units arithmetically taken into account. The tactile measuring device 47 is preferred as an electrical measuring device formed, which represents the relative position of the button 49 to the carriage 21 Emits length information signal. Correction of the length measurement information of the linear guide unit 7 or 17 can then take place automatically by a computing circuit. On the arm 33 can also be a control switch controlled, for example, by the nose 51 of the head 37 55 may be provided, which detects the rotational position of the head 37 and the coordinate direction The control signal representing the measurement for controlling the measured value display or the machine tool delivers.

On the table 1 is a rotary pick-up head 57 with an upwardly open one Receiving cone 59 for the steep taper shank of a tool 61 around a direction of displacement the linear guide unit 17 can be rotated parallel to the table plane 3 perpendicular axis of rotation stored. By means of a locking pin 63, the rotary receiving head 57 is in predetermined Rotation positions can be fixed.

The rotary receiving head 57 penetrates the table 1 and is equipped with precision ball bearings 65 stored. On the underside of the table 1, the rotary receiving head 57 carries a Handwheel 67, which has a threaded spindle (not shown in detail) at 69 indicated collet axially adjusted. The collet 69 engages in the usual way at the head of the steep taper shank and is used over partial areas for pulling in the steep taper shank opened or closed in the receiving cone 59.

While the steep taper shank is being drawn in or released, the Rotary pick-up head 57 locked. After releasing the locking pin 63, the tool 61 can be rotated by means of the handwheel 67 to measure its true running properties.

The button 49 is aligned to the rotary pick-up head 57 that its probe tip in every position of the carriage 13, 21 and in every rotational position of the head 37 is moved in one and the same plane in which the axis of rotation of the rotary receiving head 57 lies.

The table 1 carries a perpendicular to the displacement directions Linear guide units 7, 17 extending over the table surface 30 rising stop rail 71, which makes it easier to align workpieces when measuring length. In Fig. List also shows an adapter 73 with a steep taper shank 75. about which Turning tool holder 77 can be inserted into the receiving cone of the rotating receiving head 57 can.

The head 37 carries in addition to the Tastmeßgerät 47 a means a knurled screw detachably attached scriber 79 for precision-measured scribing tasks.

3 to 5 show details of the linear guide units 7 and 17. The guide rails 11 and 19 and the associated carriages 13 and 21 are constructed in the same way, so that in the following only details of the linear guide unit 7 will be explained.

The guide rail 11 is designed as a profile rail and has a essentially rectangular outline. In the two narrow long sides the Guide rails are two opposite one another in the longitudinal direction extending longitudinal grooves 81, 83 incorporated, the mutually directed Side surfaces 85 and 87, respectively, symmetrical to the common longitudinal center plane of the two Longitudinal grooves 81, 83 are inclined towards one another in a V-shape. The carriage 13 has a box profile and surrounds the guide rail 11. In a side wall covering the groove 81 89 of the carriage 13 four precision rollers 91 are arranged, which are paired with parallel axis of rotation in pairs and at a distance from one another on the guide surfaces 85 are present.

Between the side wall 93 of the opposite side wall 89 Slide 13 and the longitudinal groove 83 is a fitting 95 in the direction of the common The longitudinal center plane of the longitudinal grooves 81, 83 is movable perpendicular to the direction of displacement arranged. The fitting piece 95 also carries four precision rollers 97, the corresponding the precision rollers 91 are aligned with the guide surfaces 87. The fitting 95 is on two cylindrical ones arranged at a distance from one another in the direction of displacement Dowel pins precisely guided. As best shown in Fig. 4, is between a pressure plate 101 of an adjusting screw 103 penetrating the side wall 93, a disk spring assembly 105 clamped, which presses the fitting 95 between the guide surfaces 87. Since the guide surfaces 85 on the one hand and 87 on the other hand taper in opposite directions, any play between the carriage 13 and the guide rail 11 is resiliently compensated. Since the guide surfaces 85 and 87 lie within the guide rail 11, they are protected from damage.

The length measuring scale 25 (Fig. 2) is attached to a scale rail 107, which is also protected in a longitudinal groove 109 on a broad side of the guide rail 11 is housed. At 111 is the scale rail 107 scanning with the Slide 13 connected measuring head shown.

3 also shows details of the friction roller drive 15. This comprises one mounted on the slide 13 via an axle 112 by means of a handwheel 113 rotatable friction roller 115 made of rubber-elastic material.

The friction roller 115 is due to suitably selected dimensions with radial bias on a rolling surface 117 of the guide rail 11. By the bias becomes a flattening and thus a certain self-locking effect achieved. Instead of the friction roller drive, however, a rack and pinion drive can also be used or a spindle drive can be used.

Claims (16)

Claims 1. Two-coordinate length measuring device, comprising a Table (1) with at least one receptacle (57, 71) for a tool or workpiece, two linear guide units (7, 17), each of which is two linear relative to one another displaceable guide elements (11, 13, 19, 21) and a relative position of the two guide elements (11, 13, 19, 21) detecting and one representing the relative position Information signal generating length measuring device (25, 27), wherein one the guide elements (11) of a first (7) of the two linear guide units (7, 17) is firmly connected to the table (1) and one of the guide elements (21) the second linear guide unit (17) carries a feeler element (49) and the other guide element (19) of the second linear guide unit (17) fixed to the other guide element (13) the first linear guide unit (7) is held in such a way that the feeler element (49) with relative displacement of the guide elements (11, 13, 19, 21) in the directions of displacement the two linear guide units (7, 17) can be moved relative to the table (1), characterized in that the feeler element is a movable feeler (49) of a length feeler measuring device (47) and for the length measurement in turn relative to the length probe (47) holding guide element (21) of the second linear guide unit (17) linear is displaceable and that the length measuring device (47) by one to the plane of the displacement directions of the two linear guide units (7, 17) vertical axis of rotation rotatable on one Guide element (21) of the second linear guide unit (17) held and by means of an index locking device (51, 53) with the directions of displacement of the linear guide units (7, 17) parallel displacement direction of the button (49) can be locked. 2. Length measuring device according to claim 1, characterized in that the Table (1) a flat support surface (3) parallel to the direction of displacement of the first Linear guide unit (7) and perpendicular to the direction of displacement of the second linear guide unit (17) and both a rotary holder for tools (57) carries the axis of rotation parallel to the direction of displacement of one of the two linear guide units (7, 17) runs as well as a straight stop shoulder protruding over the support surface (3) (71) perpendicular to the directions of displacement of both linear guide units (7, 17) forms. 3. Length measuring device according to claim 1 or 2, characterized in that that in each case one of the guide elements of each linear guide unit as elongated Guide rail (11, 19) and the other guide element than along the guide rail (11, 19) displaceable carriage (13, 21) is formed that the guide rail (11) of the first linear guide unit (7) parallel to the support surface (3) of the table (1), in particular attached at both ends to the table (1) and the guide rail (19) of the second linear guide unit (17) with one of its ends on the slide (13) the first linear guide unit (7) is attached. 4. Length measuring device according to claim 3, characterized in that the Slide (21) of the second linear guide unit (17) has a transverse, in particular approximately perpendicular to the directions of displacement of the two linear guide units (7, 17) protruding Arm (33) carries, at the free end of the length measuring device (47) remote from the slide is stored. 5. Length measuring device according to claim 4, characterized in that the Length measuring device (47) on a head (37), in particular detachable during operation is held that the head (37) is rotatable in a bearing flange (35) of the arm (33), but axially movably mounted axis (39) carries that the axis (39) on the Head (37) axially facing away from the side of the bearing flange (35) an abutment head (43) carries that between the abutment head (43) and the bearing flange (35) a compression spring (41) is clamped, which clamps the head (37) axially against the bearing flange (35) and that the index locking device (51,53) mutually complementary, axially projecting or re-entrant lugs (51) or recesses (53) on the head (37) and the bearing flange (35) includes. 6. Length measuring device according to claim 5, characterized in that the Arm (33) for generating control signals representing the rotational position of the head (37) at least one control switch that can be controlled by lugs (51) or recesses (53) in the head (55) carries. 7. Length measuring device according to one of claims 1 to 6, characterized in that that on the table (1) a rotary recording head (57) with a receiving cone (59) for Tools (61) with a steep taper shank around a cone axis coaxial and to Direction of displacement of one of the two linear guide units (7, 17), in particular the axis of rotation parallel to the first linear guide unit is rotatably mounted. that the Rotary recording head (57) by means of an index locking device (63) in predetermined Rotational positions relative to the table (1) can be fixed and that the rotary recording head (57) a clamping device (67, 69) for clamping the steep taper shank in the receiving cone (59) carries. 8. Length measuring device according to claim 7, characterized in that the Rotary recording head (57) penetrates the table (1) and on the shaft insertion side of the receiving cone (59) axially facing away from the axis of rotation coaxial Handwheel (67) carries, by means of which a collet (69) of the Clamping device is actuated. 9. Length measuring device according to one of claims 1 to 8, characterized in that that in the receiving cone (59) an adapter provided with a steep taper shank (75) (73) is used to hold turning tool holders (77). 10. Length measuring device according to one of claims 1 to 9, characterized in that that on the length probe (47) holding guide element (21) the second Linear guide unit (17) also has a scriber (79) that can be removed during operation is held. 11. Length measuring device, in particular according to one of claims 1 to 10, characterized in that the linear guide unit (7, 17) is an elongated Guide rail (11) and a slide which can be displaced along the guide rail (11) (13) comprises that the guide rail (11) on two mutually opposite longitudinal outer sides a pair of guide surfaces each formed by a longitudinal groove (81, 83) in the longitudinal outer side (85.87) with one- to be pointed to the other and to the respective other pair of guide surfaces has V-shaped towards one another extending guide surfaces that the carriage (13) on both sides of the guide rail (11) each one of several, in the longitudinal groove engaging rotatable rollers (91, 97) existing roller set carries its rollers (91, 97) the carriage (13) on at least three spaced apart Support places along the pair of guide surfaces (85, 97) so that they can roll on this the rollers (91) of one of the two roller sets mounted on bearings fixed to the slide and the rollers (97) of the other roller set are mounted on a fitting piece (95) are, which on slide-fixed mating surfaces (99) on the longitudinal groove assigned to it (83) to be slidable, but transversely to it is firmly guided and that between the fitting piece (85) and the carriage (13) a fitting piece (85) on the longitudinal groove assigned to it (83) to be pretensioned spring (105) is clamped. 12. Length measuring device according to claim 11, characterized in that the guide surfaces of the guide surface pairs (85, 87) symmetrically to a common one The longitudinal plane of the guide rail (11) run. 13. Length measuring device according to claim 11 or 12, characterized in that that the fitting piece (85) on two in the longitudinal direction of the guide rail (11) at a distance arranged from one another, cylindrical dowel pins (99) is slidably guided. 14. Length measuring device according to one of claims 11 to 13, characterized in that that the spring (105) is designed as a plate spring or plate spring set and over an adjusting screw (103) is supported on the carriage (13). 15. Length measuring device according to one of claims 11 to 14, characterized in that that each roller set has four spaced apart rollers (91, 97) and that the spring (105) between the four rollers (97) of the fitting piece (85) on this attacks. 16. Length measuring device according to one of claims 1 to 15, characterized in that that on the carriage (13) an axis (112) is rotatably mounted, which is a non-rotatable at least in the area of its circumference made of elastic material, lengthways the guide rail (11) on this rollable friction wheel (115) and a handwheel (113) carries, the distance of the axis from the guide rail (11) is dimensioned so that there is self-locking due to the surface pressure of the rubber-elastic material of the carriage (13) relative to the guide rail (11) results.