DE7507398U - Length measurement - Google Patents

Description

DR. JOHANNA ULIDWJIlAIN QMBH

75 07 598.2 ^ Q ·· "·!.: .." I "i»! April 16, 1975

'••• II / Tl

Length measuring device

The invention relates to a length measuring device with a Scale, the division of which lies outside the neutral fiber and is scanned by a scanning unit that is on to measuring object is coupled and to a guide that is independent of the guidance of the object to be measured is movable. The object to be measured can be the slide of a machining or measuring machine.

In known length measuring devices with a scale whose division is outside the neutral fiber, bending of the scale in its position of use causes measurement errors.

The object of the invention is to provide a length measuring device To create the type mentioned at the outset, in terms of the measuring accuracy of a measuring device with in the neutral Fiber of the scale body lying division is equivalent, but is characterized by a simple design.

The invention solves the problem posed in that the scanning unit is attached to an object to be measured The driver is coupled with the interposition of joint-like components in such a way that compensation caused by deformation of the scale and / or guide inaccuracies of the scanning unit Errors is caused.

Compensation for errors caused by deformation of the scale takes place after the

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Invention in that the Abtastbau'einheit directly ι where the split bearing surface of the scale off ■ | and is articulated on the driver at the level of the neutral fiber of the scale body.

According to a further measure of the invention, a particularly high measurement accuracy can be achieved by that the scanning assembly, to which, for example, a grating scanning plate is attached, is at a first level the neutral fiber of the scale body articulated on the driver is coupled and in a second plane lying at right angles thereto at the level of the plane extending in the measuring direction Central axis of the division of the grid scanning plate is articulated on the driver. Through this coupling a compensation for errors caused by deformations of the scale in its position of use and inaccuracies in the guidance of the scanning unit be evoked.

Further features of the invention emerge from the claims.

In the drawing are exemplary embodiments of the length measurement '? preparation shown according to the invention.

E3 shows

Figure 1 schematically shows a first embodiment the coupling according to the invention,

Figure 2 is a side view of Figure 1,

Figure 3 shows a further embodiment of the coupling according to the invention,

Figure 4 is a side view of Figure 3,

FIG. 5 shows the coupling according to the invention with an encapsulated digital length measurement Facility,

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FIG. 6 shows a section along the line A-B

of Figure 5, ^

FIG. 7 a section along the LJ.nie C-D.

of figure 5

In FIGS. 1 and 2, 1 denotes the grid scale of an internal measuring device. The scanning construction j;

unit 2 carrying the grating scanning plate 3 supports | ^;

via sliding shoes 4 directly on the lattice scale 1. |

The lighting device and the photoelectronic components are also seen on the scanning unit 2. In the plane perpendicular to the dividing plane of the grating scale 1, the scanning unit 2 is guided over rollers 5/6 Bm carriers of the grating scale 1. This carrier is shown in FIG Figure!? A rigid hollow body 24 to which the lattice scale 1 is attached.

The scanning unit 2 is coupled to the object to be measured, for example a machine table, via a driver 7. The coupling takes place according to the invention in that the scanning unit 2 is articulated to the driver 7 at the level of the neutral Feser of the lattice scale 1. The Golenk is formed in Figure 1 by leaf springs 8 and 9 , the center axis of which is at the level of the neutral fiber of the lattice scale 1 lies. The leaf spring 8 is attached to the scanning unit 2 and to an angular component 11 . The leaf spring 9 is attached between the driver 7 and an angular component 12. This coupling of the scanning unit 2 at the level of the neutral fiber of the lattice scale 1 compensates for errors that are caused by deformations of the lattice scale 1 . Deformations of this kind can occur, for example, as soon as the lattice scale 1 is fastened in its holder .

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A particularly high measurement accuracy can be achieved by a further Coupling measure can be achieved in that the scanning unit 2 in a second plane perpendicular to the aforementioned coupling plane at the height of the in Central axis M of the grid graduation running in the direction of measurement the scanning plate 3 or the lattice scale 1 is articulated to the driver 7. The joints will be back formed by leaf springs 13 and 14 which are attached at the level of the central axis M of the grid scanning plate 3. The leaf springs 13 and 14 are on a U-shaped ver- binding part 10 and on the angular components 11 and 12 attached. This coupling of the scanning unit 2 at the level of the central axis M of the grating of the Scanning plate 3 can also be compensated for errors caused by guiding inaccuracies of the scanning unit 2 in the plane perpendicular to the division plane of the lattice scale 1 are caused.

FIGS. 3 and 4 show an embodiment in which the scanning unit 2 is articulated to a driver 7 ¹ by means of a leaf spring 15 at the level of the neutral fiber of the lattice scale 1. In the other, perpendicular plane, the scanning unit 2 is articulated to the U-shaped driver by means of rigid wires 16 and 17 at the level of the central axis M of the grid division of the scanning plate 3. The leaf spring 15 is attached to the scanner assembly and to a U-shaped member 18 to which the wires 16 and 17 are also attached.

FIGS. 5 to 7 show a photoelectric length measuring device in an encapsulated design, in which the coupling principle shown in FIG. 1 is used with particular advantage.
The division of the grid scale Λ * and the division of the

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Grid scanning plate J ^ are illuminated by means of a lamp through a condenser. The lighting device 19 ', which contains the lamp and the condenser, is attached to the scanning unit 2y . The light penetrating the grids 1. / 3-1 is thrown onto photo elements 20/21 (FIG. 6). The electrical output signal of the photo elements 20/21 is fed directly to an electronic up / down counter (not shown) of the type described in the German utility model 7 4-13 290 via the outputs 22/23.

The lattice scale "L" and the scanning unit 2 "are placed in a rigid hollow body 24, which is expediently made of extruded aluminum, for shielding against environmental influences. The lattice scale 1 ,. Is attached to the hollow body 24 by gluing. The scanning unit 2y. .1st guided via sliding shoes 4- directly on the grid scale 1, and via ball bearings 5 / i / 6 ^ on the hollow body 24. A ball bearing 25 which is attached to the scanning unit 2- via a leaf spring 26 and is supported on the hollow body 24 , presses the scanning unit 2 * against the guide surfaces on the lattice scale "L" and the hollow body. The hollow body 24 is closed by means of flexible, roof-shaped sealing lips 27/28 through which a slender, sword-shaped driver 29 extends.

The coupling of the scanning unit 2 * to the driver takes place as in Figure 1 and 2 by leaf springs 8 ^ and 9 * or 13 ^ and Ί ⁴ ^ · The leaf springs 8 ^ and 9 /] are at the level of the neutral router of the grid scale 1 ^ arranged. This coupling can compensate for errors caused by deformations of the lattice scale 1,. be evoked. The leaf springs 13 * and 14 ^ are arranged at the level of the central axis M of the grid scanning plate 3 ^.

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This coupling allows errors to be compensated,

which are caused by inaccuracies in the guideway on the hollow body 24-. The leaf spring 8 '' is attached to the scanning unit 2 '' and on the angular component 11, the leaf spring 9 '' is arranged on the angular component 12 '' and the protruding part 7 * of the sword-shaped driver 29. The leaf springs 13 ,, and 14 ,. are attached to the angular component 11 ,, and 12 ,, and to a U-shaped connecting part 1CL.

The invention is similar to the photoelectric shown Measuring device limited, but it is of course also in optical, inductive, capacitive measuring devices applicable.

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Claims (10)

Expectations 1.) Length measuring device with a scale, the division of which lies outside the neutral Paser and is scanned by a scanning unit which is coupled to the object to be measured and is displaceable on a guide independent of the guide of the object to be measured, characterized in that the scanning unit (2 or 2 *) on a driver (7 or 7 ¹ or 7 ^) attached to the object to be measured with the interposition of articulated components (8/9 and 13/14 or 15 and 16/17 or . ® _Λ / 9 _Λ u.) Coupled iet. 2.) Length measuring device according to claim 1, characterized in that the scanning unit (2 or 2,.) Is supported directly on the Fliärhe bearing the division of the scale (1 or 1 ^) and on the driver (7 or 7 * or . 7λ) at the level of the neutral fiber of the Scale (1 resp. is articulated. 3 «) length measuring device according to claim 1, characterized in that that the scanning unit (2 or 2 ^) in a first level at the level of the neutral fiber of the scale (1 or 1 ^) articulated on the driver (7 or 7 'or 7 / ·) is coupled and in one second plane lying at right angles to it at the height of the central axis (M) of the graduation, which runs in the measuring direction, is articulated to the driver (7 or 7 'or 7y) 4-.) Length measuring device according to claim 3 »characterized in that the scanning unit (2) is coupled with the interposition of a leaf spring (15) at the level of the neutral fiber of a lattice scale (1) on the driver (7 ¹ ) and in the other plane with the interposition by rigid pieces of wire (16/17) at the level of the central axis (M) of the grid scanning plate (3) is articulated to the driver (7 '). 5 ·) Length measuring device according to claim 4, characterized in that the leaf spring (15) is attached to the scanning unit (2) and to a U-shaped component (18) which encompasses the lattice scale (1) and that the on both sides of the Lattice scale Ci) provided wire pieces (16/17) on the aforementioned U-shaped component (18) as well as on a ^ m U-shaped, the lattice scale (1) encompassing ·.! Driver (7 ¹ ) are attached. 6.) length measuring device according to Ans ;, ruch 3 »characterized in that the scanning unit (2 or 2 *) with the interposition of two pairs of leaf springs (8/9 and 13/14 or 8 ^ / 9 ^ and. · Ϊ3η / 14 · / |) Is articulated to the driver (7 or 7 '/ 29). 7 ·) Length measuring device according to claim 6, characterized in that that the leaf springs (8 resp. 8th. 7507398 07/31/75 Q ■■■■ u. 9 I between ¹ ^ ₁ ) of one pair on an angular component (11 or 11,. And 12 or 12,.) And on the defensive unit (2 or 2,.) Respectively. are attached to the driver (V or V ,, / 29) and that the leaf springs (13 or 13 ,, and 14 baw. 14 ₁ ) deti other pair on the aforementioned angular component (11 or 11 and 12 or . 12 ,,) and are attached to a U-shaped connecting part (10 or 10,.). ö.) Length measuring device according to claim 1 to 3, characterized characterized in that the scale (1 ^) a Grid measuring lab, which together with a photoelectric working scanning unit (2 ^) in an elongated rigid hollow body (24) is introduced, which by means of flexible, roof-shaped arranged sealing lips (27 / P8) through which a driver attached to the object to be measured (29) passed through for the scanning unit (2 ^) is, is closed, and that also the drainage structure supporting the grating scanning plate (^^) unit (2,.) on the grid scale (^^) and on the Hollow body (24) is felt and on the driver (7> i / 29) in a first level at the level of the neutral fiber of the lattice scale ('! ,,> is articulated and i: i a two. lying at right angles to it Plane at the level of the central axis running in the measuring direction (M) the subdivision of the scanning reticle (3 ..) is articulated free of play. 9-) length measuring device according to claim 8, characterized in that that the scanning unit (2-) is resilient against the guide surfaces on the grid scale (1,1) and 7507398 07/31/75 Hollow body (24) is pressed and at the »* Guide surface of the lattice scale (1,.) Over 1 Sliding shoes (4 ^) and on the guide surface on; " Hollow body (24) over ball bearings (^ / 6 ,,) .4 supports. ί 10.) Length measuring device according to claim 9, characterized in that an oblique to the division plane
of the grid scale (1 ") lying, preferably '_; 'i designed as a ball bearing cone (25) provided; via a leaf spring (26) on the scanning unit (2, j) is attached and is supported under the action of fire on a surface of the hollow body (24 ·) and so the scanning unit (2 ^) with defining Force pushes against the guide surfaces on the lattice scale (1 ^) \ ind hollow body (24).