Measuring and testing – Dynamometers – Responsive to torque
Patent
1997-01-21
1999-02-23
Felber, Joseph L.
Measuring and testing
Dynamometers
Responsive to torque
73862191, 7386222, 81479, 173181, G01L 310
Patent
active
058746811
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention is based on a device for signal transmission. One such device is already known (European Patent Disclosure EP 467 262 A1), which has a first conductor, accommodated in a drive spindle, for contacting an oscillating body, and a second conductor, located outside the drive spindle, for contacting a control device. The signal transmission from the first to the second conductor is effected in contact fashion by means of wiper contacts, but can also be done contactlessly, that is, inductively or capacitively. In each case, separate signal transmission means are needed for the purpose.
SUMMARY OF THE INVENTION
In accordance with the present invention, at least one bearing, in particular a roller bearing is provided at the signal transmission means, by means of which bearing the first component is supplied so as to be axially and/or circumferentially displaceable or rotatable relative to the second component, the bearing at least partially comprises electrically conductive material, the bearing is disposed so as to be electrically insulated from both the first component and the second component, and the first conductor and the second conductor are electrically conductively connected to the bearing.
When the device is designed in accordance with the present invention, it has the advantage over the prior art that the signal transmission is effected without expensive separate signal transmission means. In this way, a simple and compact design of the device for signal transmission is possible.
BRIEF DESCRIPTION OF THE DRAWINGS
One exemplary embodiment of the invention is shown in the drawing and described in further detail in the ensuing description. FIG. 1 shows a device for signal transmission in a screw driving apparatus for ultrasonically controlled tightening of screw connections, and FIG. 2 shows an enlarged view of a detail of FIG. 1 identified by II.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIGS. 1 and 2, reference numeral 10 indicates a screw driving apparatus for ultrasonically controlled tightening of the screw connections. In such a screw driving apparatus 10, a prestressing force that may be present in a screw connection 11 shown schematically in FIG. 1 is ascertained by a known ultrasonic transit time measurement process and is used in a control device 13 as a control variable for controlling the screwing operation. Because of the high accuracy with which the prestressing force present in the screw connection 11 can be ascertained, very close tolerances with respect to the attainable set-point screw fastening values can be attained.
The screw driving apparatus 10, for electrical connection of an oscillating body 12 to the control device 13 and conversely, has connecting lines 14, 15. The oscillating body 12 is a piezoelectric crystal by way of example, which with suitable electrical excitation generates high-frequency acoustical oscillations and carries them to the screw connection 11. Conversely, the piezoelectric crystal receives echo oscillations from the screw connection 11 and converts them into associated electrical echo signals. By comparison of the exciter signals and echo signals in the schematically shown control device 13, a conclusion can be drawn in a known manner about the state of tension in the screw connection 11 and hence about the current prestressing force.
The screw driving apparatus 10 is provided with a rotary spindle 19, which is supported in bearings 20, 21 with regard to a hollow-cylindrical housing part 22. On its end 23 toward a drive motor, not shown, the rotary spindle 19 is equipped with rotary slaving means 24, which by way of example are embodied as a receiving opening 18 for an external polygon. A drive shaft, not shown but provided with an external polygon, of a drive motor can be inserted into the receiving opening 18. On its other end 25 toward the screw connection 11, the rotary spindle 19 forms a tool receptacle 26, onto which a screw driving tool, not shown in FIG. 1 and for instance a hexagonal socket can be pl
REFERENCES:
patent: 4890501 (1990-01-01), Schumacher
patent: 5650573 (1997-07-01), Bruns et al.
Felber Joseph L.
Robert & Bosch GmbH
Striker Michael J.
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