SCREW NUT

Abstract

The present invention relates to a screw nut equipped with sensors (2, 3) on its lateral surfaces.

Claims

1. An intelligent screw nut, wherein the screw nut comprises strain gauges configured to measure compression of the screw nut, wherein the strain gauges are fixed to at least one lateral surface.

2. The intelligent screw nut according to claim 1, characterized in that the screw nut is equipped with an RFID transponder or a micro-controller.

3. The intelligent screw nut according to claim 1, characterized in that the strain gauges are oriented in the direction of the screw axis and/or transversely to the screw axis.

4. The intelligent screw nut according to claim 1, characterized in that an RFID transponder or micro-controller is connected to the strain gauges sensors by means of a sensor cable.

5. The intelligent screw nut according to claim 1, characterized in that an RFID transponder or micro-controller is fixed to a lateral surface or multiple lateral surfaces of the screw nut.

6. The intelligent screw nut according to claim 1, characterized in that sensor measurement signals are transmitted from one lateral surface to another lateral surface of the screw nut by means of a sensor cable.

7. The intelligent screw nut according to claim 1, characterized in that sensor measurement signals are transmitted from one lateral surface to another lateral surface of the screw nut by means of radio technology.

8. The intelligent screw nut according to claim 1, characterized in that the strain gauges are glued or welded to the at least one lateral surface.

9. The intelligent screw nut according to claim 1, characterized in that the screw nut is equipped with an RFID transponder, wherein the RFID transponder comprises an analog-to-digital converter and an amplifier.

10. The intelligent screw nut according to claim 1, characterized in that the screw nut is equipped with the RFID transponder is a passive RFID transponder.

11. The intelligent screw nut according to claim 1, characterized in that the screw nut further comprises a temperature sensor.

12. The intelligent screw nut according to claim 11, characterized in that the temperature sensor is designed to measure the temperature of the screw nut.

13. The intelligent screw nut according to claim 2, characterized in that the RFID transponder or the micro-controller is designed to wirelessly transmit measurement signals of the strain gauges to a receiver.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] FIGS. 1 to 4 show schematic views of an inventive screw nut according to a first example in different projection views;

[0065] FIGS. 5 and 6 show schematic views of an inventive screw nut according to a second example;

[0066] FIG. 7 shows a schematic perspective view of an inventive screw nut according to a third example;

[0067] FIGS. 8 and 9 show schematic views of an inventive screw nut according to a fourth example in different projection views;

[0068] FIG. 10 shows a schematic top view of an inventive screw nut according to a fifth example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0069] FIGS. 1 to 4 show schematic views of an inventive screw nut 1 according to a first example in different projection views, in lateral view (FIGS. 1 and 3) and in top and bottom view (FIGS. 2 and 4).

[0070] The screw nut 1 comprises two sensors 2, which are arranged on opposite lateral surfaces 8 of the screw nut 1 and are configured as strain gauges. The direction of measurement 9 of the strain gauges extends substantially parallel to the screwing axis/the screw axis 4 of the nut 1, which is substantially defined by the orientation of the internal threads of the nut 1.

[0071] The two sensors 2 are connected to one another via sensor cables so that the measurement signal can be read out via a single transmitter. The transmitter is configured as a passive RFID transponder 5 with an analog-to-digital converter and an amplifier. As a result, the measuring arrangement does not require a permanent power supply; instead, the energy required for measuring and reading out the measured value is supplied by an external readout device (not shown).

[0072] FIGS. 5 and 6 show schematic views of an inventive screw nut 1 according to a second example. The screw nut 1 is screwed on a threaded bolt 7 and, via a washer 11, presses against an element 12 to be fastened. The compression of the nut 1 is inversely proportional to the tensioning force. In contrast to the first example, this screw nut 1 comprises only one sensor 2 and two RFID transponders 5.

[0073] FIG. 7 shows a schematic perspective view of an inventive screw nut 1 according to a third example. On one lateral surface 8, an RFID transponder 5 is arranged; the sensor 2 is not shown.

[0074] FIGS. 8 and 9 show schematic views of an inventive screw nut 1 according to a fourth example in top view (FIG. 8) and in lateral view (FIG. 9).

[0075] The screw nut 1 comprises two sensors 2, which are arranged on opposite lateral surfaces 8 of the screw nut 1 and are configured as strain gauges. Further, on one lateral surface 8 with a sensor 2 a further sensor 3 is provided, which is configured as a strain gauge. The direction of measurement 9 of the sensors 2 extends substantially parallel to the screwing axis/the screw axis 4 of the nut 1, while the direction of measurement 9 of the sensor 3 extends substantially transversely/orthogonally to the screwing axis/the screw axis 4 of the nut 1.

[0076] For transmitting the measured values, two RFID transponders 5 are provided.

[0077] Among other things, the sensor 3 serves to determine strains and compressions of the screw nut 1, which are not caused by a change of the tensioning force, but by temperature fluctuations, for example.

[0078] In an example which is not shown, the sensor 3 may be replaced by a temperature sensor, in order to determine temperature fluctuations and be able to determine the strain/compression of the screw nut 1 resulting therefrom.

[0079] FIG. 10 shows a schematic top view of an inventive screw nut 1 according to a fifth example. Here, two sensors 2 are provided, which are configured as strain gauges and the direction of measurement of which extends parallel to the screw axis 4. Further, two sensors 3 are provided, which are configured as strain gauges and the direction of measurement of which extends orthogonally to the screw axis 4. To simplify matters, the RFID transponder 5 and other elements are not shown.

LIST OF REFERENCE SIGNS

[0080] 1 Screw nut

[0081] 2 Sensor

[0082] 3 Sensor

[0083] 4 Screw axis

[0084] 5 RFID transponder/micro-controller

[0085] 6 Sensor line

[0086] 7 Threaded bolt/screw

[0087] 8 Lateral surface

[0088] 9 Direction of measurement

[0089] 10 Screw

[0090] 11 Washer

[0091] 12 Element