Torque measuring device

#Applicant claims priority under 35 U.S.C. §119 of German Application No. 102 17 416.4 filed Apr. 18, 2002.

#1. Field of the Invention

#The present invention relates to a torque measuring device, in particular for use with commercially available tools.

#Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It should be understood, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the invention.

#In the drawings,

#FIG. 1 shows an exploded illustration of the torque measuring device according to an embodiment of the invention with all the individual parts,

#FIG. 1 shows an exploded illustration of all the individual parts of a torque measuring device 1, including a connecting element 2 provided for torque transmission and a measuring head housing 3, and also the further individual parts needed to measure the torque.

#Connecting element 2 serves primarily to transmit the torque and is subjected to the torsional loading. Connecting element 2 includes a round pin with an integrally molded square 4 at one end and an integrally molded square socket 5 at the opposite end. Square 4 is designed to accommodate a commercially available bolt socket, for example a nut or the like and, for the purpose of retention and locking, has a locking ball 7 embedded in a hole 6. Square socket 5 is enlarged radially with respect to connecting element 2. In this way, an internal square recess is formed, into which a torque-producing tool, for example a device driven by electric motor or pneumatically and having a square can be inserted. Formed on the outer surface 8 in the axial direction is an axial groove 9, in which a corresponding spring belonging to measuring head housing 3 engages, so that measuring head housing 3 is firmly connected to connecting element 2 on one side so as to rotate with it. Measuring head housing 3 can further be secured on connecting element 2 by an axial securing ring, in order that the housing cannot slip off connecting element 2. Fixing measuring head housing 3 to connecting element 2 on one side ensures that, when torsional loading of connecting element 2 occurs, this loading is not transmitted to measuring head housing 3. In the central shaft region, connecting element 2 has a surface-ground or chamfered contact face 10, on which a measuring element 11 is fixed. Measuring element 11 may take the form, for example, of a strain element, a piezo-electric element, a linear Hall sensor element, a ceramic strain element or a resilient magnetic element. Measuring element 11 is, for example, adhesively bonded to contact face 10, so that torsional deformations of connecting element 2 which occur are transmitted to measuring element 11. The measuring elements 11 listed convert the torsional and compressive stresses which occur into a measured value which can be fed to further electronics, for example via a Wheatstone measuring bridge, so that evaluation of the torque achieved is possible.

#Viewed in cross section, measuring head housing 3 is of approximately circular construction and is equipped with two planar faces 12, 13 machined in the circumferential face. However, these planar faces have no particular significance, and a circular measuring head housing 3 or any other desired cross section can likewise be selected. Following assembly, connecting element 2 is embedded coaxially in measuring head housing 3 in an aperture 14, in which there are formed the springs, not visible, which engage in axial groove 9 of connecting element 2. Following assembly, measuring head housing 3 is closed by a housing cover 15, housing cover 15 being fixed by means of screws 16. On its inner side 17, housing cover 15 has an axial recess, in which a disc-like plate 18 is embedded following assembly. In the region of screws 16, plate 18 is equipped with cutouts 19, so that screws 16 can engage in measuring head housing 3.