PITCH MEASURING DEVICE AND METHOD FOR CHECKING AN ADJUSTMENT PRECISION OF A COMPONENT MOVING ON A MOTION PATH

Abstract

A pitch measuring device for checking a positioning precision of an operating spindle or an operating table of a machine, e.g. of a NC machine tool moving along an at least two dimensional movement path, the pitch measuring device including a measuring device including a rotary encoder and an electronics unit detecting an angular position of a housing base element relative to a housing top element wherein the measuring device is attachable at a machine arm receiving the operating spindle or at a machine table. Additionally a pendulum element can be used that is connected in a rigid manner with the measuring device and which includes a pendulum element with an integrated first inclination sensor which is supplemented by a second inclination sensor which is directly attachable at frame element of the machine.

Claims

1. A pitch measuring device for checking a positioning precision of a machine element of a machine, the machine element moving along an at least two dimensional movement path, the pitch measuring device comprising: a housing including attachment devices for attachment of the housing at the machine element, an integrated measuring device that is arranged in the housing, a centrally arranged rotation shaft, a rotary encoder for detecting an angular position of the rotary encoder relative to the rotation shaft, wherein the housing includes a housing base element and a housing top element that is rotatably arranged relative to the housing base element through the rotation shaft that is centrally arranged and attached torque proof at the housing base element, wherein the rotary encoder is arranged in the housing top element and the housing base element includes the attachment devices.

2. The pitch measuring device according to claim 1, wherein the housing top element includes a clamping pin that is arranged in alignment with an axis of the rotation shaft.

3. The pitch measuring device according to claim 1, wherein the housing top element includes a housing cover and a housing jacket.

4. The pitch measuring device according to claim 1, wherein the housing top element includes electrical connection devices configured as plug connectors for different operating modes of the pitch measuring device.

5. The pitch measuring device according to claim 1, wherein the housing base element includes a plug connector which is connected with the housing top element through slip contacts, and wherein the slip contacts are connected with plug connectors or an electronic circuitry in an electrically conductive manner.

6. The pitch measuring device according to claim 1, wherein the housing base element includes a base that includes a pressure plate and with an actuation plate, wherein the actuation plate is provided for attachment of the housing base element at the machine element and the pressure plate clamps a base of the rotation shaft with the actuation plate, and wherein orientation devices are arranged between the actuation plate and the pressure plate.

7. The pitch measuring device according to claim 1, further comprising an external data unit that is connectable with a computer, wherein the external data unit is connectable or connected at a plug connector or at other measuring elements.

8. The pitch measuring device according to claim 1 further comprising, a first inclination sensor that is attachable at the housing top element and a second inclination sensor that is attachable directly at a frame element of the machine.

9. The pitch measuring device according to claim 8, wherein a first pendulum element which is removably attached or attachable at a clamping pin of the housing top element includes the first inclination sensor and a second pendulum element that is directly attachable at the frame element of the machine includes the second inclination sensor.

10. The pitch measuring device according to claim 8, wherein the housing base element includes a combined data output for the rotary encoder and the first inclination sensor, wherein the combined data output is configured as a combination plug connector or the housing top element includes a respective data output for the rotary encoder and a respective data input for the inclination sensor arranged at the housing top element, and wherein the respective data outputs are configured as individual plug connectors.

11. A method comprising the steps: moving a machine element of a machine along a movement path that is at least two dimensional, and checking a positioning precision of the machine element by a pitch measuring device, the pitch measuring device including: a housing including attachment devices for attachment of the housing at the machine element, an integrated measuring device which includes a centrally arranged rotation shaft and a rotary encoder in the housing for detecting an angular position of the rotary encoder relative to the rotation axle, wherein the housing is arranged at the machine element performing the movement path with the horizontal rotation shaft, wherein a first inclination sensor is arranged at the housing and a second inclination sensor is arranged at a frame element of the machine and data provided by the first inclination sensor and the second inclination sensor during a position change of the machine is computed with data determined by the rotary encoder.

12. The method according to claim 11, wherein measurement values provided by the first inclination sensor and the second inclination sensor are zeroed before the measurement.

13. The method according to claim 11, wherein deviations from an original position at a beginning of a measurement are added to or subtracted from measurement values provided by the rotary encoder.

14. The method according to claims 11, wherein a pitch measuring device according to claim 1 is used.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention is subsequently described in more detail based on an embodiment with reference to drawing figures. Additional features of the invention can be derived from the subsequent description of the embodiment of the invention in combination with the claims and the appended drawing figures. The individual features of the invention can be implemented individually or in combination in different embodiments of the invention, wherein:

[0028] FIG. 1 illustrates a perspective view of the pitch measuring device including a housing including a housing base element and a housing top element;

[0029] FIG. 2 illustrates a perspective view of the inner elements of the housing top element;

[0030] FIG. 3 illustrates a sectional view of the pitch measuring device according to FIG. 1;

[0031] FIG. 4 illustrates a perspective view of a pitch measuring device including a pendulum element;

[0032] FIG. 5 illustrates a block diagram for a measurement without the pendulum element; and

[0033] FIG. 6 illustrates a block diagram for a measurement with two pendulum elements.

DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1 illustrates the pitch measuring device 1 including a cylindrical housing 2 that includes a housing top element 2 and a housing base element 2. The housing top element 2 and the housing base element 2 are rotatable relative to each other through a rotation shaft 3 (FIG. 3) that is not visible in this illustration. The housing top element 2 includes a housing cover 4 and a housing jacket 5. Individual connection jacks 6, 6 are provided in the housing cover 4 wherein the connection jacks are provided as individual plug connectors for connecting connection cables for the respective measuring purposes. In this embodiment the connection jack 6 is used for data output of a rotary encoder 7 (FIGS. 2, 3) arranged in the housing top element 2 for normal operations without additional sensors. The connection jack 6 is required when the pitch measuring device 1 is additionally operated with an inclination sensor. In this case the connection socket 6 is not required. In the embodiment the connection jack 6 is provided with eight poles and the connection jack 6 is provided with four poles. Centrally arranged and in an extension of the rotation shaft 3 and the rotation axis thus formed a clamping pin is arranged at the housing cover 4. The scanning rod arrangement that is typical for the measurement can be attached at the clamping pin 10 by a clamping element which is fixed with another end at a stationary machine element or a machine element relative to the moving machine element at which the housing 2 of the pitch measuring device 1 is attached. Thus, a rotation movement of the housing top element 2 is prevented so that the measurement can be performed by the rotation of the housing base element 2 relative to the housing top element 2. The clamping pin 10 is simultaneously used for attaching a pendulum element with an inclination sensor 21 (FIG. 4) which is clamped together with the clamping pin 10.

[0035] The housing base element 2 includes a base 11 that is offset from the housing top element 2. The housing base element 2 furthermore includes an additional jack 12 which is also used in a form of a combination plug connector as a data output for the signals from the rotary encoder 7 when the inclination sensor 21 is connected through the connection jack 6. The jack 12 is configured as a 12 pole jack. The signals from the rotary encoder 7 and the connection jack 6 are captured from the rotation shaft 3 by slip rings 25 (FIG. 3). Corresponding adapters for attaching and securely fixing the housing 2 can be attached in a known manner at the base 12 at a machine element that moves and is to be measured. The base 11 also includes adjustment devices with adjustment screws 18 that are externally accessible and offset from each other by 90 for orienting the housing top element 2 relative to the housing base element 2. For this purpose the base 11 includes a pressure plate 15 and an adjustment plate 16 which are connected with each other through screws 19 with plate springs.

[0036] FIG. 2 illustrates the embodiment in the upper housing top element 2. At this location the rotary encoder 7 with a scanning head 8 and a bearing ring 26 with encoding and a substantially no clearance ball bearing are arranged and a converter circuit board 14 on a carrier circuit board 27 for the rotary encoder 7 which circuit board is attachable at the housing cover 4. The converter circuit board 14 has connections for the rotary encoder 7 and the connection jack 6, 6 and is also used to amplify and process the analog sine shaped signals.

[0037] The sectional view of FIG. 3 with a sectional line extending through the plug connector jack 12 and the scanning head 8 illustrates the housing jacket 5 with the housing cover 4 of the housing top element 2 with the individual components in an interior of the housing top element 2. The rotation shaft 3 associated with the housing base element 2 and fixed at the base 11 and associated with the rotary encoder 7 is coaxial with the clamping pin 10. The bearing ring 26 with an encoding with 30,000 lines is arranged on the rotation shaft 3. This yields a measuring precision of0.6 angle seconds. The exact angle position is then determined by the scanning head 8 with the respective precision. A slip ring 25 transfers the signals to the plug in jack 12. On an inside of the housing cover 4 there is the converter circuit board 14 on which the signals supplied by the scanning head 8 or the connection jack 6 are accordingly provided either to the connection jack 6 or the plug in jack 12 through respective cables that are not illustrated.

[0038] The housing base element 2 includes the base 11 which is connected with the rotation shaft 3. The base 11 includes the upper pressure plate 15 and the lower actuation plate 16 wherein the pressure plate 15 is disengageable from the actuation plate 16 by the bolts 19 so that the rotation shaft 3 can be aligned in the radial direction with the rotation shaft base 3 in a cavity 17 arranged in the actuation plate 16 wherein the alignment is performed by adjustment screws 18. After the adjustment the pressure plate 15 can be bolted to the actuation plate 16 by bolts 19 with plate springs so that the rotation axis of the rotation shaft 3 is fixed. Through the radial movement of the rotation shaft 3 also the housing top element 2 is aligned accordingly.

[0039] The pitch measuring device 1 illustrated in FIGS. 1-3 facilitates measurements in all positions in space of the moving machine component. In FIG. 4 the pitch measuring device 1 is illustrated with a pendulum element 9 arranged at the housing top element 2. In this application of the pitch measuring device 1 the pitch measuring device is attached at the moving machine element so that the rotation shaft 3 or the rotation axis is horizontal. Only for this configuration a measurement with the pendulum element 9 is possible. The pendulum element 9 is fixed with a clamping opening 20 at the clamping pinion 10 and thus arranged so that the pendulum element 9 is disposed between the two connection jacks 6, 6. The pendulum element 9 includes a non-illustrated inclination sensor 21 in an interior of the pendulum element wherein the inclination sensor detects deviations from vertical and a converter circuit board 14. The inclination sensor 21 is thus also connected with the connection jack 6 through a connection cable that is also not illustrated.

[0040] FIG. 5 illustrates the circuit arrangement for the major portion of the measurements without the pendulum element 9. The measurement values are transmitted by the scanning head 8 through corresponding 8 strand cables to the converter circuit board 14 and through the connection jack 6 and a connection cable plugged into it to an analog digital converter 22 in which the analog signals are digitized. Thereafter the digital signals are transmitted through a corresponding connection converter 24 (USB) to a computer with an input unit 23. There the deviations from the nominal value are determined by addition or subtraction. The converter circuit board 14 is used for signal amplification and signal processing for the signals provided by the scanning head 8.

[0041] In order to perform the measurement using a pendulum element 9 drawn in dashed lines at the housing 2 it is necessary to arrange a second pendulum with another inclination sensor 21 that is also drawn in dashed lines and configured accordingly at the machine frame of the machine. FIG. 6 illustrates the associated circuitry. According to FIG. 6 an analog digital converter 22 is provided which digitizes the input signals. The actual rotation angles supplied by the scanning head 8 with the changes provided by the inclination sensors 21 and 21 relative to the position at the beginning of the measurement are corrected by addition or subtraction in the computer 23. The determined correction values are either put in by hand through the computer or through the input terminal 23 or directly into the machine control. The signals captured by the scanning head 8 are provided through an 8 strand cable to the converter circuit board 14. The measurement values of the inclination sensor 21 of the pendulum element 9 are transmitted to a converter circuit board 14 and through the jack 6 to the rotation shaft 3 with the slip ring and are transmitted through the plug in jack 12 to the AD converter 22.

[0042] Through the jack 12 also the inclination sensor 21 in a pendulum element 9 that is attached at the machine frame is connected through a converter circuit board 14 arranged in the pendulum element 9 is connected with the A/D converter 22. The connection cables to the inclination sensors 6, 6 have four strands. The converter circuit board 14 and the converter circuit board 14 are used for signal amplification and signal processing of the analog signals like the converter circuit board 14.