Screw tightening device with integrated detection means

Abstract

To provide a screw tightening device that eliminates or significantly reduces the disadvantages of the prior art. [Solution] A screw tightening device (10) that applies torque to a screw partner (20) comprises a flat output means (1) having an output part (1b) that can be detachably connected to the screw partner and a drive part (1a) that can apply drive torque manually or mechanically via an intervening angle and / or bevel gear device (31), and a detection means (5) that provides measured values ​​used to determine and / or monitor the output torque acting on the screw partner on the output part side, wherein the detection means (5) provided in the housing (30) of the flat output means (1) is connected to transmit torque to the drive part and output part of the flat output means (1), and the detection means (5) is configured to detect radial and / or tangential forces acting on a straight-tooth gear (4d), and can provide the radial and / or tangential forces for electronic signal evaluation.

Description

[Technical field]

[0001] The present invention relates to a screw tightening device for applying a torque to a screw partner, the screw tightening device comprising integrated detection means for detecting the output torque. [Background technology]

[0002] From the prior art, in particular from industrial screw tightening technology, screw tightening devices with geared offset head means are generally known. Geared offset head means are usually gear units accommodated in a flat housing, which usually comprise a drive part at one end and an output part at the opposite end to which a screw partner (such as a screw to which a torque is applied) can be attached (preferably detachably). Such screw tightening devices are used in particular for screw tightening and assembly operations of screw partners that are difficult to reach due to spatial installation conditions.

[0003] For quality assurance reasons, particularly in industrial applications, or for documentation purposes, it is desirable to detect or monitor the output torque acting on the respective screw partner on the output side. A typical screw tightening device is already known from WO 2018 / 188829 A1. WO 2018 / 188829 A1 discloses detection means assigned to the geared offset head means and detecting the axial force acting on the helical gear of said geared offset head means, whereby the output torque acting on the screw partner on the output side can be determined. However, in order to perform such a determination by evaluating the detected axial force, an additional axial bearing must be provided, which increases the design complexity of the structural arrangement in the geared offset head means. Furthermore, the known detection means require additional installation space in the geared offset head means. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2018 / 188829A1 (Special table 2020-516914) Summary of the Invention [Problem to be solved by the invention]

[0005] Based on the already known prior art, the object of the present invention is to provide an improved screw tightening device, which overcomes or at least significantly reduces the disadvantages of the above-mentioned prior art, in particular by providing an alternative means for determining and / or monitoring the torque acting on the screw partner on the output side, while at the same time allowing for a cost-effective and compact design of a geared offset head, and by allowing a reliable torque determination and monitoring. Furthermore, the present invention addresses other objects, which are described in more detail in the following description.

[0006] The object of the present invention is achieved by a screw tightening device for applying a torque to a screw partner, the screw tightening device having the features of the independent claim 1. Advantageous embodiments of the invention are described in the dependent claims. [Means for solving the problem]

[0007] A first aspect of the present invention is a screw tightening device for applying a torque to a screw partner, comprising: an output part detachably connectable to said screw partner and preferably an intervening - a geared offset head means with a drive to which a drive torque can be applied manually or mechanically via an (intermediate) angle and / or bevel gear arrangement; and detection means for providing measured values ​​used to determine and / or monitor the output torque acting on said thread partner on the output side, said detection means provided on a housing of said offset gear head means is adapted to detect radial and / or tangential forces acting on a gear, preferably having a straight tooth profile, connected to transmit torque to said drive and output portions of said geared offset head means; The screw tightening device is characterized in that the detection means are capable of providing the radial and / or tangential forces, preferably for electronic signal evaluation.

[0008] The arrangement of the detection means according to the invention, which is integrated into the housing of the geared offset head means and detects radial and / or tangential or circumferential forces of the gears interacting with the detection means in the geared offset head means, provides a simple design solution for reliable measurement values ​​for determining and / or monitoring the output torque acting on the output screw partner. In particular, the installation space required by the geared offset head means can be minimized compared to the already known prior art. Furthermore, the arrangement of the screw tightening device according to the invention allows for cost-effective production and simple maintenance. Furthermore, the linear meshing of the gears interacting with the detection means increases the efficiency of the geared offset head means. The measurement values ​​for determining and / or measuring the output torque preferably refer to the radial and / or tangential forces detected by the detection means or to measurement values ​​or measurement signals representative thereof.

[0009] In particular, the simplicity of the design of the invention for generating electronically assessable signals allows for a compact and cost-effective realization of an (electronic) interface function for standardized external assessability and / or a (preferably wireless) signal transmission to the outside by means of miniaturized electronic components. In particular, the electrical energy supply means provided for such electronic interface or signal processing means according to embodiments within the scope of the invention allow such wireless self-contained and therefore flexible functioning in addition to the power supply means as the electrical energy supply means. For example, a generator solution may be an option in additional embodiments. Such a power generation process advantageously utilizes the rotation of the associated gear parts which necessarily occurs in the screw tightening device according to the invention, and this mechanical kinetic energy can be converted in a generally known manner into electrical operating energy for the above-mentioned functions. The advantages of independence from a battery or other wired power source are also evident.

[0010] The above-mentioned radial and / or tangential forces acting on the gears refer to radial and / or tangential forces, respectively, acting on the gears, in particular radial and / or tangential forces acting on the gears when in operative connection with other gears or gear trains meshing with the gears. The radial and / or tangential forces acting on the gears refer in particular to bearing reaction forces of the gears in the radial and / or tangential directions, detectable by the detection means. Preferably, in this step, radial and / or tangential forces, respectively, acting on the bearings or rotation shaft of the gears (preferably fixed to the housing) when a torque is transmitted in the gears connected to the detection means are detected. Here, the radial and / or tangential forces preferably refer to forces in a plane substantially perpendicular to the rotation shaft of the gears and / or the main axis of the geared offset head.

[0011] In a particularly preferred exemplary embodiment, the detection means is configured to detect tangential or circumferential forces applied to the gears, preferably acting in the same direction, and radial forces on or along a line of action which are or can be combined to obtain a resultant force, the radial forces detected in this process being forces applied to the gears or bearing reaction forces of the gears.

[0012] When the gear interacting with the detection means according to the present invention has a straight tooth profile, When the gear is in operative connection or interaction with another gear or gear train meshing with it at the geared offset head means, preferably only rotational forces are introduced into the gear, so that only radial and / or tangential forces act on the gear. Preferably no axial forces, i.e. forces along the rotation axis of the gear, occur. In this case, a measurement signal reliably representative of and / or monitoring the torque on the output side can be provided by the detection means, preferably for electronic signal evaluation.

[0013] If the gear wheel interacting with the detection means according to the invention has or is a helical gear wheel, in addition to the radial and / or tangential forces, axial forces or reaction forces acting in said axial direction on the gear wheel occur. Preferably, these additional forces are not detected by the detection means according to the invention. However, a measurement signal for reliable monitoring of the output torque can be provided by the detection means, preferably for electronic signal evaluation. In particular, from deviations in the detected radial and / or tangential forces, it can be determined that there is a deviation in the output torque.

[0014] In a preferred embodiment, the gear interacting with the detection means according to the invention is arranged between the drive assembly of the offset geared head means with a gearing and the output assembly of the offset geared head means with a gearing. In this embodiment, the gear interacting with the detection means according to the invention is preferably configured as a gear that directly interacts or meshes with the output assembly. Alternatively, the output assembly can directly include the gear interacting with the detection means according to the invention. For example, the straight tooth gear itself can constitute the output assembly of the offset geared head means. In this way, both variants can realize the substantial advantages of the invention, i.e. according to the invention, the measurement value at the output side of the offset geared head means can be detected as accurately as possible by means of the detection means.

[0015] In a preferred embodiment, the offset geared head means comprises a number of gears forming a gear arrangement between the drive and output of the offset geared head means. In this embodiment, the gear interacting with the detection means according to the invention is preferably one of the gears forming the gear arrangement. The gear arrangement may comprise straight tooth gearing or helical gearing. The gear arrangement may also comprise angle, bevel and / or spiral gearing.

[0016] In a preferred embodiment, the offset geared head means comprises a plurality (at least two, preferably at least three) of straight tooth gears or helical gears. Particularly preferably, the offset geared head means comprises only straight tooth gears. However, alternatively, the offset geared head means may comprise at least some helical gears. All of the rotation axes of the gears of the offset geared head means preferably extend in one plane. The rotation axes preferably extend parallel to one another and pass through a flat surface of the housing of the offset geared head.

[0017] The housing of the geared offset head preferably has two parallel flat faces or opposing planar outer surfaces. Preferably, these faces are free of protrusions or projections. The housing is preferably two-part, having two opposing halves. The maximum width of the housing is preferably less than 30mm, more preferably less than 20mm.

[0018] The gear wheel interacting with the detection means preferably has a bearing shaft which is fixed, in particular non-rotatably fixed, to the housing, on which a ring gear of the gear wheel is rotatably mounted, preferably by means of a needle bearing. The detection means preferably comprises at least one force transducer, which is preferably rigidly connected, in particular non-rotatably connected or integrally formed with the bearing or the bearing shaft of the gear wheel. In this case, the force transducer is preferably arranged non-rotatably between the bearing shaft and the housing of the geared offset head means. Also in this case, the force transducer may be fixed in a recess of the housing cover by a suitable pin connection with the housing cover and / or by corresponding shaping so as not to rotate relative to the housing.

[0019] The force transducer is preferably arranged on a line of action of a resultant force applied to the gear, the line of action being radial to the gear. Preferably, this resultant force is a radially acting force and tangential or circumferential forces applied to the gear, preferably acting in the same direction, are or can be combined to obtain a resultant force. In particular, the force transducer is preferably arranged to detect radial forces on or along the line of action.

[0020] The force transducer is preferably realized in the form of a spoke wheel and / or is preferably disk-shaped in nature. The force transducer preferably consists of the same material as the assigned gear and / or the bearing shaft of the gear. The force transducer is preferably formed or arranged on the end face of the gear. In particular, the force transducer can be arranged directly on the gear ring edge of the gear. More preferably, two force transducers, preferably of the same type, can be formed or arranged on both end faces of the gear.

[0021] The force transducer is preferably arranged such that no transmission of forces from the force transducer to the housing of the geared offset head means occurs in the axial direction, ie in particular along the axis of rotation of the gear wheel.

[0022] The force transducer may be arranged or formed coaxially and / or rotationally symmetrically with the gear to which it is arranged. The outer diameter or maximum radial extension of the force transducer is preferably approximately the same as the circular base of the gearing of the assigned straight tooth gear. The thickness of the force transducer in the axial direction is preferably in the range of 1 mm to 5 mm, more preferably in the range of 1 mm to 2.5 mm.

[0023] In a preferred embodiment, the force transducer comprises integrated force sensor means arranged to detect compressive and / or tensile forces applied to the force transducer in a radial and / or tangential direction of the gear or the force transducer, the force sensor means being preferably arranged on a line of action of a resultant force applied to the gear, the line of action extending in said radial direction.

[0024] The force sensor means preferably comprises at least one strain gauge attached to the force transducer. Preferably at least two strain gauges are arranged or attached to the force transducer. Preferably, the strain gauges are arranged on the radially extending spokes or struts of the force transducer, preferably on opposing spokes or struts. Alternatively or additionally, the force sensor means may comprise a piezo element.

[0025] Alternatively or additionally, the force sensor means may comprise hydraulic or pneumatic sensor means attached or connected to the force transducer, which may then comprise at least one, and preferably two, suitable chambers consisting of recesses or cavities, for example in which a liquid suitable for reading the hydraulic or pneumatic sensor is placed or introduced, preferably said chambers being arranged opposite each other in the force transducer and arranged in each half of the force transducer.

[0026] Alternatively or additionally, the force sensor means comprises a polymer body comprising graphene, preferably with variable electrical conductivity, which is attached or integrated in the force transducer. For example, the polymer body can be introduced into suitable chambers consisting of recesses or cavities in the force transducer, for example chambers arranged opposite each other, preferably in each half of the force transducer. Preferably, the polymer body comprises a viscoelastic polymer body comprising graphene, such as a boron-containing silicone-based elastic putty. Such conductive polymer bodies having integrated particles or flakes of graphene and which exhibit a variable electrical resistance when the pressure applied to the polymer body is changed are known from Zeitschrift Science, 9, 12. 2016, Vol. 354, Ausgabe 6317, Seiten 1257-1260.

[0027] The sensor means can provide a measurement signal representative and / or monitoring of the torque at the output, preferably for electronic signal evaluation, with high reliability and with a high level of measurement quality and accuracy. The detection means may comprise means for wireless signal transmission of a measurement signal dependent on the detected output torque and / or for monitoring the output torque. In addition to this, the detection means may comprise electronic interface and / or signal processing means and electrical energy supply means. The electrical energy supply means may be realised as generator means interacting with moving, in particular rotating, parts of the offset gearhead means.

[0028] The measurement signals provided by the detection means can be transmitted to a computing unit arranged or connectable to the screw tightening device, which evaluates the detected signals and calculates and / or monitors the respective output torques on the basis of the evaluation of the detected signals. This can for example be done on the basis of information in a comparison table and / or database. The information in the comparison table and / or database can for example comprise the measured values ​​of the detection means determined in a series of tests and associated respective torque values ​​which can be used to calculate and / or monitor the respective output torques on the basis of the given measured values. In this case, the computing unit can be configured to detect deviations from a definable target value and to emit an alarm or warning signal if the deviations are too large, for example by more than 10%, more preferably by more than 5%.

[0029] The offset geared head means according to the invention is preferably a closed or open offset geared head means. The offset geared head means may be of an angle gear or non-angle gear design. The offset geared head means may also comprise a spiral gearing, for example as part of an angle gear. In this case, the detection means according to the invention may be assigned to a gear with a spiral gearing and may interact with said gear to detect the radial and / or tangential forces acting on said gear.

[0030] Another aspect of the invention relates to a screw tightening system (preferably hand-held or stationary) comprising the above screw tightening device and a driving torque generating means connected to said geared offset head means on the drive side. The driving torque generating means is preferably configured in the form of a manually operable or automatic screwdriver. By stationary screw tightening system is meant a screw tightening system which is preferably permanently installed in a production unit (e.g. a robotic cell) and which is preferably operable by automatic control means.

[0031] Further advantages, configurations and details of the present invention are apparent from the following description of preferred exemplary embodiments and the drawings. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a perspective view of a screw tightening system according to a preferred exemplary embodiment of the present invention; [Diagram 2] FIG. 2 is a perspective view of a geared offset head means according to the present invention with the housing partially removed; [Figure 3a] FIG. 13 is a perspective view showing a gear wheel interacting with the detection means; [Figure 3b] FIG. 3b is a partial cross-sectional view of the gear of FIG. 3a. [Figure 3c] FIG. 3c is a perspective view of the force transducer of FIGS. 3a and 3b; [Figure 3d] FIG. 13 is a perspective view of an alternative embodiment of a force transducer. [Figure 4a] FIG. 13 shows a perspective view of another preferred embodiment of a gear wheel interacting with detection means comprising hydraulic or pneumatic sensor means. [Figure 4b] FIG. 4b is a cross-sectional view of a gear wheel interacting with the detection means shown in FIG. 4a; [Diagram 5] FIG. 1 shows a perspective view of another preferred embodiment of a force transducer according to the present invention, comprising a sensor means comprising a polymer portion containing graphene and having variable electrical conductivity. [Figure 6] FIG. 13 is an exemplary schematic diagram showing forces applied to a gear interacting with a detection means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] 1 shows a preferred embodiment of a screw tightening device 10 according to the invention for applying a torque to a screw partner 20, such as a screw. The screw tightening device 10 comprises a geared offset head means 1 with an output part 1b detachably connectable to the screw partner 20 and a drive part 1a by which a drive torque can be applied manually or mechanically, for example via an intervening angle and / or bevel gearing 31.

[0034] The screw tightening device 10 can be preferably selectively coupled to a screw tightening device 30, thereby forming a screw tightening system 40 according to the invention. The screw tightening device 30 can be a standard device, and a torque can be introduced, for example electrically or pneumatically, by a motor via an intervening angular and / or bevel gearing 31, into the geared offset head means 1 of the screw tightening device 10. The driving torque thus introduced is transmitted by the geared offset head means 1 to a device 32, provided as output 1b as described below, for the screw tightening operation of the screw partner 20. The screw tightening device 10 comprises a flat housing 30, preferably made up of two housing halves 30a, 30b of substantially the same shape. Preferably, the maximum height or width b of the housing 30 is 30 mm, more preferably 20 mm.

[0035] 2 shows an offset gear head means 1 according to the invention in a perspective view with the housing partially removed. The geared offset head means 1 comprises a drive assembly 2 for interacting with, for example, an angular and / or bevel gear arrangement 31 on the drive side and an output assembly 3 for interacting with the screw partner 20, for example via an implement 32 connected to the screw partner and on the output side.

[0036] The geared offset head means 1 preferably comprises a number of gears 4a, 4b, 4c, 4d, 4e which form a gear arrangement between the drive part 1a and the output part 1b of the geared offset head means 1. These gears are preferably straight tooth gears, for example with a transmission ratio of 1:1. As an alternative to the configuration shown in Fig. 2, said gears can also be realised as helical gears. Different transmission ratios are also possible.

[0037] The gears are preferably arranged axially parallel in the housing 30 and extend linearly along the longitudinal extension of the housing 30, in which the gears are arranged rotatably. The drive assembly 2 or the output assembly 3 may comprise some of the gears. Preferably, the drive assembly 2 and the output assembly 3 each comprise a gear train or a gear 4a, 4e, which is in operative connection with the other gears of the gear arrangement. In particular, the drive assembly 2 and the output assembly 3 may each be constituted by a gear 4a, 4e.

[0038] Such a geared offset head means 1 is provided for normal manual screw tightening operations and is suitable for transmitting a maximum torque of about 200 Nm. The typical efficiency of such a straight tooth gear arrangement (i.e. the ratio of the torque at the output side 4e to the torque at the drive side 4a) is in the range of about 85% to 95%, depending on the lubrication conditions and the exact design of the gearing.

[0039] The detection means 5 is arranged between the drive assembly 2 and the output assembly 3, the detection means 5 being configured to provide a measurement value for determining and / or monitoring the output torque acting on the screw partner 20 on the output side. The detection means 5 is assigned to or is in operative connection with a gear 4d, preferably having a straight tooth profile. The gear 4d connected to the detection means 5 preferably meshes with a gear 4e of the output assembly 3. Alternatively, the gear 4d connected to the detection means 5 may be directly included in or constitute the output assembly 3.

[0040] Fig. 6 is a schematic diagram showing the linear arrangement of the gears 4c, 4d, and 4e having the straight tooth profile shown in Fig. 2. In the free body diagram of the meshing gears 4c, 4d, and 4e shown as an example in the figure, the tangential or circumferential forces F 1a ,F 1b and F 2a ,F 2b are shown to act in the illustrated Y direction in the engaged state of the gearing and are approximately perpendicular to the extension direction X of the gear arrangements 4c, 4d, 4e. The origins of the forces in the engaged state of the gearing are shown on either side of the central gear 4d by way of example. The magnitudes of these forces differ only in the possible efficiency losses within the gear stages. Two circumferential forces F acting in the same direction 1a ,F 1b and F 2a ,F 2b When the resultant force is obtained by combining the above forces, the line of action W of these forces is located approximately at the center of the gear 4d. Therefore, the detection means 5 according to the present invention is preferably disposed on the line of action of the resultant force applied to the gear 4d, or disposed so as to be able to detect a force occurring on or along the line of action.

[0041] FIG. 3a shows a perspective view of a gear wheel 4d and corresponding or assigned detection means 5. FIG. The detection means 5 comprises a force transducer 5a, preferably substantially disk-shaped, in the form of a spoke wheel (see also FIG. 3c), which is for example integrally formed and / or rigidly (in particular non-rotatably) connected to the axis of rotation 19 of the gear 4a. Furthermore, the force transducer 5a is non-rotatably attached to the housings 30a, 30b, for example by means of axially provided bores 9a, 9b and connecting pins (not shown) accommodated therein. As an alternative to this, the force transducer 5a can be attached to said housings in a shape-retaining manner. In this case, the outer shape of the force transducer 5a (see FIG. 3d) can be approximately trapezoidal, for example in a shape that can be accommodated or mounted non-rotatably in a corresponding recess of the housings 30a, 30b.

[0042] The force transducer 5a is preferably arranged on an end face 6a of the gear 4d or on the axis of rotation 19 of the gear 4d. The detection means 5 preferably comprise two force transducers 5a, which are preferably of the same type, arranged on two opposite end faces 6a, 6b of the gear 4a or on the axis of rotation 19 of the gear 4d (see FIG. 3b).

[0043] The gear 4d preferably comprises a central rotation shaft 19, which is provided with a bore 19a in which the geared offset head means 1 is arranged, preferably non-rotatably, and / or is arranged to guide a sensor line or wiring 13 assigned to the detection means 5. The shaft 19 preferably has, at both ends, a portion 19b, which protrudes in the axial direction and is arranged for at least one force transducer 5a to be attached and / or coupled thereto. The portion 19b can in particular be engaged, preferably non-rotatably, in the central bore 8 of the force transducer 5a. Between the force transducer 5a and the main shaft of the shaft 19, a spacer or drill disk 21 can be arranged. A ring gear 22 of the gear 4d is arranged rotatably on the shaft 19, preferably by means of a needle bearing 23.

[0044] The force transducer 5a has a central bore 8 for coupling the force transducer 5a to the rotating shaft 19 and / or for guiding the sensor wire 13. The force transducer 5a preferably has a circular outer shape. The outer diameter d or maximum radial extension of the force transducer 5a is preferably smaller than or approximately the same as the circular shape of the base of the gear 4d. The thickness t of the force transducer 5a is preferably in the range of 1 mm to 5 mm, more preferably in the range of 1 mm to 2.5 mm.

[0045] The force transducer 5a comprises at least two (preferably opposing) radial struts or bars 7a, 7b and an intermediate recess 11a, 11b, 11c, 11d, preferably of a generally arcuate shape. The force transducer 5a may comprise radially extending struts or bars 7a, 7b, 7c, 7d, defined by an inner circle 18a and an outer circle 18b formed coaxially with the inner circle.

[0046] The force transducer 5a comprises integrated or mounted force sensor means arranged to detect radial and / or tangential compressive and / or tensile forces with respect to the gear 4d, which are applied as bearing reaction forces to the force transducer and thus to a bearing shaft 19 connected for rotation therewith. In the embodiment shown in figures 3a to 3c, the force sensor means are constituted by strain gauges 12a, 12b mounted on the force transducer 5a. The strain gauges 12a, 12b are arranged on the radially extending struts 7a, 7b of the force transducer 5a, preferably on opposing struts, so as to detect in particular compressive and / or tensile forces acting on the assigned gear 4d when these struts interact with the gears 4c, 4e which mesh with the assigned gear. The struts 7a, 7b or force sensor means 12a, 12b are preferably arranged along or parallel to the line of action W (see also FIG. 6) of the resultant force applied to the gear 4d in each gear arrangement.

[0047] A signal can be provided by the sensor wiring 13 in a manner known per se for further processing and evaluation. Preferably, a voltage variation as a result of the elastic deformation due to the radial force is generated by a strain gauge as force sensor means, which voltage variation is provided for electronic signal evaluation and in particular for determining and / or monitoring the torque on the output side. To provide a measurement signal for electronic signal evaluation, the device can be equipped with means for wireless signal transmission (not shown). The signal evaluation can be performed by a computing means (not shown) assigned to the device or which can be connected to the device, which computing means for example calculates or monitors a corresponding or applied torque on the basis of the oscillated voltage signal. For example, the signal evaluation can be performed on the basis of a comparison table stored in a database. Since the gear 4d according to the invention and the force transducer 5a connected to it directly mesh with the gear 4a of the output assembly 3 and the output torque is directly introduced into the screw partner 20 for screwing, the force sensor signal can very accurately and reproducibly indicate or monitor the actual torque ratio on the output side of the offset gearhead means without interference, thus realizing the object of the invention. The loss due to torque coupling in this manner is negligible.

[0048] In figures 4a and 4b another preferred embodiment of the detection means 5 according to the invention is shown, in which the force transducer 5a comprises hydraulic or pneumatic sensor means. In particular, the force transducer 5a comprises at least one, preferably two suitable chambers 14a, 14b, said chambers consisting of recesses or cavities in which a suitable fluid is placed or introduced. The chambers 14a, 14b are preferably arranged opposite each other in the force transducer 5a and symmetrically along the axis A dividing the force transducer 5a into two halves. The changes in the hydraulic or pneumatic pressure in the chambers 14a, 14b, caused by the interaction of the gear 4d with the gears 4c, 4e meshing with it, can be detected by means of suitable pressure sensors assigned to the chambers 14a, 14b. The transmission to the pressure sensors arranged outside the force transducer 5a can be carried out by means of suitable lines 14c, 14d. Each of the chambers 14a, 14b may have a filling and / or venting opening 24, which can optionally be closed by a corresponding plug (not shown). The sensor means can then cause a corresponding electronic signal to be emitted, from which the torque applied to the gear 4d can be deduced.

[0049] As shown in Fig. 4b, the detection means 5 preferably comprises two force transducers 5a provided on the two end faces 6a, 6b of the gear 4d or on the rotation shaft 19. As shown in the figure, each chamber 14a, 14b is preferably connected or linked by a channel 25 preferably formed in or guided within the rotation shaft 19.

[0050] In Fig. 5, another preferred embodiment of the detection means 5 according to the invention is shown, in which the force transducer 5a comprises a polymer part containing graphene and having variable electrical conductivity as sensor means. In particular, the force transducer 5a comprises at least one, preferably two suitable chambers 15a, 15b, said chambers consisting of recesses or cavities in which the polymer part containing graphene is introduced and which are in contact with corresponding electric wires 16a, 16b and 17a, 17b, respectively. The chambers 15a, 15b are preferably arranged symmetrically along the axis B, which divides the force transducer 5a into two halves. Preferably, radially extending spring elements 26 are arranged in the chambers 15a, 15b as supporting structural elements.

[0051] The electrical conductivity of the graphene-containing polymer part varies when a torque is applied to the gear 4d and thus generates a reaction force on the force transducer 5a interacting with the gear 4d, thereby enabling a torque-dependent sensor signal to be generated for electronic signal evaluation.

[0052] The above-described embodiments are merely exemplary, and the invention is not limited to the embodiments shown in the drawings. In particular, the exemplary embodiments shown in the drawings can be combined with each other. The following are some aspects included in the present invention. [Aspect 1] A screw tightening device (10) for applying torque to a screw partner (20), a geared offset head means (1) comprising an output part (1b) removably connectable to said thread partner (20) and a drive part (1a) capable of applying a driving torque manually or mechanically, in particular via an intervening angular and / or bevel gearing (31); and detection means (5) for providing measurements used to determine and / or monitor the output torque acting on said thread partner (20) on the output side, The detection means (5) provided in the housing (30) of the geared offset head means (1) detects the driving portion (1a) of the geared offset head means (1). and configured to be capable of detecting radial and / or tangential forces acting on a gear (4d), preferably with a straight tooth profile, connected to the output portion (1b) so as to transmit torque; 13. A screw tightening device (10), characterized in that the detection means (5) are capable of providing the radial and / or tangential forces, preferably for electronic signal evaluation. [Embodiment 2] A screw fastening device as described in embodiment 1, characterized in that the geared offset head means (1) is provided with the gear (4d) that interacts with the detection means (5) between a drive assembly (2) having a gear device and constituting the drive section (1a) and an output assembly (3) having a gear device and constituting the output section (1b), or the output assembly (3) is provided with the gear (4d) that interacts with the detection means (5). [Embodiment 3] A screw fastening device as described in embodiment 1 or 2, characterized in that the geared offset head means (1) is provided with a plurality of gears (4a, 4b, 4c, 4d, 4e) that form a gear arrangement between the drive unit (1a) and the output unit (1b), and the gear (4d) that interacts with the detection means (5) is preferably one of the gears (4a, 4b, 4c, 4d, 4e) that form the gear arrangement. [Aspect 4] A screw fastening device as described in any one of aspects 1 to 3, characterized in that the geared offset head means (1) has a plurality of gears (4a, 4b, 4c, 4d, 4e), and the rotation axes of the plurality of gears preferably extend in a common plane. [Embodiment 5] A screw fastening device according to any one of embodiments 1 to 4, characterized in that the detection means (5) includes at least one force transducer (5a) arranged on a line of action (W) of a resultant force applied to the gear (4d), the line of action (W) extending radially relative to the gear. [Embodiment 6] A screw tightening device as described in embodiment 5, characterized in that the force transducer (5a) is arranged on the end face (6a) of the gear, preferably coaxially with the gear, and / or the maximum outer diameter (d) or maximum radial extension of the force transducer (5a) approximately corresponds to the circular shape of the base of the gear (4d). [Embodiment 7] A screw fastening device according to embodiment 5 or 6, characterized in that the force transducer (5a) is firmly connected to or integrally formed with the bearing (19) of the gear (4d). [Embodiment 8] A screw tightening device as described in any one of embodiments 5 to 7, characterized in that the force transducer (5a) is provided with an integrated force sensor means configured to detect compressive and / or tensile forces applied radially and / or tangentially to the force transducer (5a). [Embodiment 9] A screw tightening device as described in embodiment 8, characterized in that the integrated force sensor means is composed of strain gauges (12a, 12b) attached to the force transducer (5a) and preferably arranged on opposing struts (7a, 7b) of the radially extending force transducer (5a). [Embodiment 10] A screw fastening device as described in embodiment 8, characterized in that the integrated sensor means is constituted by a hydraulic or pneumatic sensor means (14a, 14b) attached or connected to the force transducer (5a). [Embodiment 11] A screw tightening device according to embodiment 8, characterized in that the integrated sensor means is constituted by a polymer part (15a, 15b) containing graphene and having variable electrical conductivity, in particular a viscoelastic polymer part containing graphene, such as a boron-containing silicone-based bouncing putty, and the polymer part (15a, 15b) is attached to or integrated with the force transducer (5a). [Embodiment 12] A screw fastening device as described in any one of embodiments 1 to 11, characterized in that the detection means (5) is provided with a signal transmission means, preferably wireless, for transmitting a measurement value signal corresponding to the detected output torque and / or monitoring the output torque. [Embodiment 13] A screw fastening device as described in any one of embodiments 1 to 12, characterized in that the detection means (5) comprises an electronic interface and / or signal processing means, and an electrical energy supply means. [Aspect 14] A screw fastening device as described in aspect 13, characterized in that the electrical energy supply means is realized as a generator means interacting with moving parts, in particular rotating parts, of the offset gear head means. [Aspect 15] A screw fastening device (10) according to any one of aspects 1 to 14, and a driving torque generating means (30) connected to the geared offset head means on the drive side.

Claims

1. A screw tightening device (10) for applying a torque to a screw partner (20), comprising: a geared offset head means (1) comprising an output part (1b) removably connectable to said thread partner (20) and a drive part (1a) capable of applying a driving torque manually or mechanically, in particular via an intervening angular and / or bevel gearing (31); The geared offset head means (1) is provided in a housing (30) of the geared offset head means (1), and the output Determination and / or modeling of the output torque acting on the threaded partner (20) at the outer side. and detection means (5) configured to provide measurements for use in a monitor, the detection means (5) is adapted to detect radial and / or tangential forces acting on a gear (4d), preferably with straight teeth, connected to transmit torque to the drive portion (1a) and the output portion (1b) of the geared offset head means (1); said detection means (5) being capable of providing said radial and / or tangential forces for electronic signal evaluation, said detection means (5) comprising a generally disk-shaped force transducer (5a) with integrated force sensor means configured to detect compressive and / or tensile forces applied radially and / or tangentially to said force transducer (5a); The integrated force sensor means comprises graphene and a polymer with variable electrical conductivity.

1. A screw tightening device (10) comprising a polymer part (15a, 15b) attached to or integral with the force transducer (5a).

2. A screw tightening device (10) for applying a torque to a screw partner (20), comprising: a geared offset head means (1) with an output part (1b) removably connectable to said thread partner (20) and a drive part (1a) capable of applying a drive torque manually or mechanically, in particular via an intervening angular and / or bevel gearing (31); and detection means (5) arranged on a housing (30) of said geared offset head means (1) and configured to provide measurements used to determine and / or monitor an output torque acting on said thread partner (20) on the output side, the detection means (5) is adapted to detect radial and / or tangential forces acting on a gear (4d), preferably with straight teeth, connected to transmit torque to the drive portion (1a) and the output portion (1b) of the geared offset head means (1); said detection means (5) being capable of providing said radial and / or tangential forces for electronic signal evaluation, said detection means (5) comprising a generally disk-shaped force transducer (5a) with integrated force sensor means configured to detect compressive and / or tensile forces applied radially and / or tangentially to said force transducer (5a); 1. A screw tightening device (10) characterized in that the integrated force sensor means is comprised of strain gauges (12a, 12b) attached to the force transducer (5a) and arranged on opposing struts (7a, 7b) of the radially extending force transducer (5a).

3. 3. The screw fastening device according to claim 1 or 2, characterized in that the geared offset head means (1) is provided with the gear (4d) interacting with the detection means (5) between a drive assembly (2) having a gear device and constituting the drive part (1a) and an output assembly (3) having a gear device and constituting the output part (1b), or the output assembly (3) is provided with the gear (4d) interacting with the detection means (5).

4. A screw fastening device according to any one of claims 1 to 3, characterized in that the geared offset head means (1) comprises a plurality of gears (4a, 4b, 4c, 4d, 4e) constituting a gear arrangement between the drive part (1a) and the output part (1b), and the gear (4d) interacting with the detection means (5) is preferably one of the gears (4a, 4b, 4c, 4d, 4e) constituting the gear arrangement.

5. 5. The screw tightening device according to claim 1, wherein the geared offset head means (1) comprises a plurality of gears (4a, 4b, 4c, 4d, 4e), the rotation axes of which preferably extend in a common plane.

6. 6. The screw tightening device according to claim 1, wherein the force transducer (5a) is arranged on a line of action (W) of a resultant force applied to the gear (4d), the line of action (W) extending radially relative to the gear.

7. 7. The screw tightening device according to claim 1, characterized in that the force transducer (5a) is arranged on an end face (6a) of the gear, preferably coaxially with the gear, and / or the maximum outer diameter (d) or maximum radial extension of the force transducer (5a) approximately corresponds to the circular base of the gear (4d).

8. 8. The screw tightening device according to claim 1, wherein the force transducer (5a) is rigidly connected to or integral with the bearing (19) of the gear (4d).

9. The screw fastening device according to claim 1 or any one of claims 3 to 8 when dependent on claim 1, characterized in that the polymer portion (15a, 15b) is a boron-containing silicone-based bouncing putty.

10. 10. The screw tightening device according to claim 1, wherein the detection means (5) comprises means for transmitting, preferably wirelessly, a measurement signal depending on the detected output torque and / or monitoring the output torque.

11. 11. A screw tightening device according to any one of the preceding claims, characterized in that the detection means (5) comprise electronic interface and / or signal processing means and electrical energy supply means.

12. 12. The screw tightening device according to claim 11, characterized in that the electrical energy supply means is realized as a generator means interacting with a moving, in particular a rotating, part of the geared offset head means.

13. A screw tightening device (10) according to any one of claims 1 to 12, a drive torque generating means (30) connected to the geared offset head means on the drive side; A handheld or stationary screw tightening system (40) comprising:

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