Method for operating a manual machine tool and manual machine tool

Abstract

[Solution] The present invention relates to a method for operating a manual machine tool, the manual machine tool including an electric motor, the method comprising the following method steps: S1 comparison information is provided, comprising the following method steps: S1a at least one model signal shape (240) is provided, the model signal shape (240) being assignable to a work progress of the manual machine tool (100); S1b a coincidence threshold is provided; S2 a signal of an operating variable (200) of the electric motor (180) is determined; S3 the comparison information and the signal of the operating variable (200) are analyzed, comprising the following method steps: S3a the signal of the operating variable (200) is compared with the model signal shape (240) and a coincidence signal is determined from the comparison; S3b a coincidence assessment is determined, the coincidence assessment being performed at least in part with reference to the coincidence threshold and with reference to the coincidence signal; S4 work progress is recognized at least in part with reference to the coincidence assessment determined in method step S3; and the provision of the comparison information is performed at least in part based on an automated evaluation of the coincidence signal. Further, the present invention relates to a manual machine tool.

Description

[Technical Field]

[0001] The present invention relates to a method for operating a manual machine tool and to a manual machine tool set up for carrying out this method. [Background technology]

[0002] A rotary impact driver for tightening threaded elements such as screw nuts and screws is known from the prior art, see, for example, Patent Document 1. This type of rotary impact driver includes a structure in which a striking force in one rotational direction is transmitted to the threaded element by the rotary striking force of a hammer. A rotary impact driver having such a structure includes a motor, a hammer to be driven by the motor, an anvil struck by the hammer, and a tool. In the rotary impact driver, the motor assembled in the housing is driven, the hammer is driven by the motor, and the rotating hammer further strikes the anvil, thereby releasing the striking force to the tool, and two different operating states, namely "no striking action" and "striking action," can be distinguished.

[0003] From DE 10 05 04 199 A1 an electrically driven tool with a striking mechanism is also known, in which a hammer is driven by a motor.

[0004] When using a rotary impact driver, a high degree of concentration on the work process is required on the part of the user to switch certain machine characteristics, for example, when starting or stopping the striking mechanism, in order to react accordingly, for example, to stop the electric motor and / or to change the rotation speed via a manual switch. Because the user is often unable to react quickly enough or adequately to the work process, when using a rotary impact driver, for example, over-turning of screws can occur during the screwing process, or during the unscrewing process, screws can fall out if they are loosened and turned at too high a rotation speed.

[0005] It is therefore generally desirable to substantially automate the operation and reduce the burden on the user by appropriate responses or routines in the tool released by the machine, thus ensuring a reproducible, high quality screwing and unscrewing process. Examples of such responses or routines released by the machine include switching off the motor, changing the motor speed, or issuing a message to the user.

[0006] The provision of such intelligent tool functions can be achieved, inter alia, by identifying the operating state currently occurring. In the prior art, this is achieved by monitoring the operating variables of the electric motor, such as the rotational speed or the electric motor current, independently of the work progress determination or application status. The operating variables are then checked to see whether certain limit values ​​and / or threshold values ​​have been reached. Corresponding evaluation methods are also implemented using absolute threshold values ​​and / or signal gradients.

[0007] The disadvantage here is that the fixed limit values ​​and / or threshold values ​​can in fact only be perfectly set for one application case: as soon as the application case changes, the associated current values ​​and / or rotational speed values ​​or their time course also change, and impact recognition with reference to the set limit values ​​and / or threshold values ​​or their time course no longer works.

[0008] For example, an automatic switch-off that relies on the recognition of a striking action may reliably switch off at various speed ranges in some applications using tapping screws, but may not switch off in other applications using tapping screws.

[0009] In some cases, the user can, for example, adjust the parameters to adapt the sensitivity of the motor response to the current screwdriving case. After the parameters have been properly adjusted, the end of the screwdriving process can be recognized and the appropriate motor response can be released accordingly. However, such parameter adjustment presupposes some experience in handling the corresponding manual machine tool, is time-consuming, and does not lead to satisfactory results in all cases. Therefore, it would be desirable to simplify the operation so that adjustments on the user's side are no longer necessary.

[0010] Another method for determining the operating mode in a rotary impact driver utilizes an additional sensor, such as an acceleration sensor, to infer the operating mode occurring at that time from the vibration state of the tool.

[0011] The drawback of such a method is the additional cost incurred for the sensors as well as the loss of robustness of the manual machine tool, since the number of components and electrical connections incorporated increases compared to a manual machine tool without such a sensor device.

[0012] Furthermore, the simple information of whether the striking mechanism is activated or not is not sufficient to provide adequate information about the work progress. For example, when driving a certain wood screw, the rotary striking mechanism is activated very early, during which the screw is not yet completely screwed into the material, but the required torque already exceeds the so-called release torque of the rotary striking mechanism. In other words, a response based purely on the operating state of the rotary striking mechanism (striking and no striking) is not sufficient for accurate automatic system functioning of the tool, for example for switching it off.

[0013] Essentially, the problem of substantially automating the operation also exists in other manual machine tools, such as percussion drills, and therefore the invention is not limited to rotary impact drivers only. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] European Patent Application Publication No. 3381615 [Patent Document 2] German Utility Model No. 202017003590 Summary of the Invention [Problem to be solved by the invention]

[0015] The object of the present invention is to provide an improved method for operating a manual machine tool, which at least partially obviates the above-mentioned drawbacks, or to provide at least one alternative to the prior art. A further object is to provide a corresponding manual machine tool. [Means for solving the problem]

[0016] This problem is solved by the subject matter of the respective independent claims. Preferred embodiments of the invention are the subject matter of the respective dependent claims.

[0017] According to the present invention, a method for operating a manual machine tool having an electric motor is disclosed, the method comprising the following method steps: S1 Comparative information is provided and includes the following method steps: S1a at least one model signal shape is provided, the model signal shape being assignable to a work progress of a manual machine tool; S1b Thresholds for agreement are provided; S2 The signal of the operating amount of the electric motor is determined; S3 The comparison information and the signals of the operating quantities are analyzed, which comprises the following method steps: S3a. The signal of the operating quantity is compared with a model signal shape, and a match signal is determined from the comparison; S3b a match assessment is determined, the match assessment being made at least in part with reference to a match threshold as well as with reference to the match signal; S4 Work progress is recognized at least in part with reference to the match assessment determined in method step S3.

[0018] In accordance with the present invention, it is contemplated that the provision of comparison information is based at least in part on an automated evaluation of the match signals.

[0019] The present invention simplifies the operation of manual machine tools in that no parameter adjustment is required by the user. Accordingly, the end of the screwdriving process can be automatically recognized by the machine, regardless of external conditions such as the screw type or material. In response, in some embodiments of the present invention, appropriate routines of the manual machine tool, such as a motor response, can be released in method step S5, based at least in part on the work progress recognized in method step S4. This functionality has the advantage of being implemented without the aid of additional hardware components, such as various sensors, and is therefore achieved solely by analyzing already existing signals, such as the motor speed signal. This eliminates the need for parameter adjustment by the user. Therefore, the motor response can be automatically released, regardless of the material or screw type.

[0020] The method of the present invention effectively supports the user of a manual machine tool in achieving reproducible, high-quality application results, and in particular allows the user to more easily and / or quickly achieve fully completed work progress.

[0021] The impact driver then responds in some embodiments by recognizing the impact condition and work progress by detecting characteristic signal shapes.

[0022] Various routines may provide one or more system functionalities to the user, allowing the user to complete an application case more easily and / or quickly.

[0023] Some embodiments of the present invention can be typified as follows: 1. Embodiments including "pure" hit recognition routines or responses; 2. Embodiments including routines or responses to non-hit recognition; 3. An embodiment including a routine or response to work progress (hit rating / hit quality).

[0024] Either embodiment essentially has the advantage that it is possible to complete the application case as quickly and completely as possible, which simplifies the work for the user.

[0025] Those skilled in the art will recognize that the term "model signal shape" includes signal shapes of continuous progress of a work process. In one embodiment, the model signal shape is a state-typical model signal shape that is state-typical for a specific work progress of a manual machine tool, such as a screw head resting on a mounting base or a loose screw running idle.

[0026] The approach of recognizing the work progress through the operating quantities of the measured quantities inside the tool, such as the rotation speed of an electric motor, has proven to be particularly advantageous, since this method allows the work progress to be determined with particularly high reliability and almost independently of the overall operating state of the tool or its application case.

[0027] In this case, in particular additional sensor units, such as acceleration sensor units, for detecting measured quantities inside the tool are basically dispensed with, so that essentially only the method according to the invention serves to recognize the work progress.

[0028] In an embodiment of the present invention, the coincidence signal reflects a constant or varying, in particular time-varying, error corresponding to the difference between the model signal and the signal of the operating quantity.

[0029] In one embodiment, the automated evaluation of the coincidence signal comprises determining characteristics of the coincidence signal, such as slope, curvature, or local or global minimum or maximum. The determination of the characteristics of the coincidence signal is carried out in a mathematical sense, for example by one or more differentiations of the coincidence signal, which exists as a time progression or as a progression of an electric motor quantity correlated with the time progression. In this case, numerical differentiation and curve approximation techniques known per se can be applied.

[0030] The determination of the coincidence signal may include the determination of an error, defined in an appropriate manner, between the model signal and the signal of the operating quantity, possibly as a time progression or as a progression of the quantity of the electric motor correlated with the time progression.

[0031] The match threshold can then be determined, e.g., estimated, based at least in part on the characteristics of the match signal, without any adjustment of the match threshold by the establishment or by the user.

[0032] Furthermore, the coincidence assessment in step S3b can be performed at least partly based on the frequency of the signal of the operating quantity. In this embodiment, in addition to the coincidence signal, the frequency of the rotational speed signal, measured for example during the percussion operation, is additionally determined, for example calculated or measured. Since this frequency changes during the screwdriving process, the coincidence signal can be used to determine the working progress of the manual machine tool, for example to recognize the end of the screwdriving case and release an appropriate motor response.

[0033] In an embodiment of the invention, it is determined whether this frequency is above or below a frequency threshold, so that the match assessment in method step S3b is at least partly dependent on the frequency threshold: if the frequency is above the frequency threshold, the frequency of the signal of the operating quantity is taken into account in the match assessment in step S3b.

[0034] In certain embodiments, the match assessment in step S3b is based at least in part on a logical operation, such as an "AND", "NAND" or "OR" operation, between the match signal and the frequency of the signal of the operating quantity.

[0035] In another embodiment, the coincidence assessment in step S3b is performed at least partly based on a sum signal of the coincidence signal and the frequency of the signal of the operating quantity.

[0036] In another embodiment, the match assessment in step S3b is based at least in part on fuzzy sets or membership functions (weighting functions), see fuzzy logic.

[0037] In one embodiment, the first routine executed in step S5 includes stopping the electric motor after taking into account at least one defined and / or configurable parameter, in particular configurable by a user of the manual machine tool. Examples of such parameters include the time of day, the number of rotations of the electric motor, the number of rotations of the tool mount, the rotation angle of the electric motor, and the number of strikes of the striking mechanism of the manual machine tool.

[0038] In another embodiment, the first routine comprises changing, in particular decreasing and / or increasing, the speed of the electric motor, which can be achieved, for example, by changing the motor current, the motor voltage, the battery current, or the battery voltage, or by a combination of these measures.

[0039] Preferably, the amplitude of the change in the speed of the electric motor can be defined by the user of the manual machine tool. Alternatively or additionally, the change in the speed of the electric motor can be set by a setpoint. The term "amplitude" is to be understood in this context as meaning the magnitude of the change in general and is not only relevant to cyclic processes.

[0040] In one embodiment, the speed of the electric motor is changed multiple times and / or dynamically, in particular in a time-stepped manner and / or along a characteristic curve of the speed change and / or with reference to the work progress of the manual machine tool.

[0041] In one embodiment, the first routine includes adjusting the rotational speed of the electric motor and maintaining the rotational speed substantially constant. The rotational speed is adjusted immediately after the first routine is executed. The rotational speed is maintained substantially constant, so that the electric motor rotates at a speed substantially equal to the adjusted rotational speed. "Maintaining the rotational speed substantially constant" is understood to mean that the rotational speed may fluctuate within a range of 1% to 25% around the adjusted rotational speed. It is conceivable that the user may adjust the rotational speed. It is also possible for the rotational speed to be adjusted at the factory. Adjusting the rotational speed and maintaining it substantially constant allows the screw member to be tightened with minimal fluctuation in thread prestress.

[0042] Preferably, the progress of the first routine is output to a user of the manual machine tool using an output device of the manual machine tool. The output by the output device can be understood to mean, in particular, a display or documentation of the progress of the work. Here, the documentation can also be an evaluation and / or storage of the progress of the work. This includes, for example, storing multiple screwdriving processes in a memory.

[0043] In one embodiment, the first routine and / or characteristic parameters of the first routine are adjustable and / or viewable by a user through application software (“App”) or a user interface (“Human Machine Interface, “HMI”).

[0044] Furthermore, in one embodiment, the HMI may be located on the machine itself, whereas in another embodiment the HMI may be located on an external device, such as a smartphone, tablet, computer, etc.

[0045] In one embodiment of the present invention, the first routine includes optical, acoustic, and / or tactile feedback to the user.

[0046] In one embodiment, the method includes a method step AM in which an upper speed limit of the electric motor is adjusted. Method step AM may precede method step S1 or may follow another method step. The upper speed limit of the electric motor essentially limits the available speed of the electric motor relative to its maximum speed. The upper speed limit may be in the range of 20% to 100%, in particular in the range of 30% to 95%, and very particularly in the range of 50% to 85% of the maximum speed of the electric motor. It is conceivable that the upper speed limit can be adjusted by the user or set at the factory. Adjusting the upper speed limit allows the screw element to be screwed in with less variation in thread prestress.

[0047] It is conceivable that the upper speed limit of method step AM remains adjusted until the first routine of method step S5. It is possible that the upper speed limit remains adjusted until any one of method steps S1 to S4. In this way, the upper speed limit of method step AM remains adjusted until method step S5, and an increased speed compared to the upper speed limit can be adjusted during the first routine.

[0048] Adjustment of the upper limit of the rotational speed of the electric motor makes it possible to tighten the screw member with little variation in the thread prestress.

[0049] The model signal shape is preferably a vibration curve, for example a vibration curve around a mean value, in particular a substantially trigonometric vibration curve, which may represent, for example, an ideal striking action of a hammer against an anvil of a striking mechanism, preferably a strike without further rotation of the tool spindle of a manual machine tool.

[0050] In principle, various operating variables can be taken into consideration as operating variables to be recorded by suitable measurement generators, with the present invention having the particular advantage that no additional sensors are required in this respect, since various sensors, for example for monitoring the rotational speed, in particular Hall sensors, are already integrated into the electric motor.

[0051] The operating quantity is preferably the rotational speed of the electric motor or an operating quantity that is correlated with the rotational speed. A fixed transmission ratio from the electric motor to the impact mechanism results, for example, in a direct dependency between the impact frequency and the motor rotational speed. Another possible operating quantity that is correlated with the rotational speed is the motor current. Other operating quantities that can be considered as operating quantities of the electric motor include the motor voltage, the Hall signal of the motor, the battery current or battery voltage, as well as the acceleration of the electric motor, the acceleration of the tool mount, or the acoustic signal of the impact mechanism of a manual machine tool.

[0052] The comparison of the model signal shape with the signal of the operating quantity in step S3a preferably involves application of a frequency-based comparison method and / or a comparative comparison method.

[0053] A determination can then be made, at least in part by frequency-based comparison methods, in particular by band-pass filtering and / or frequency analysis, whether a work progress to be recognized has been identified in the signal of the operating quantity.

[0054] In one embodiment, the frequency-based comparison method includes at least band-pass filtering and / or frequency analysis.

[0055] In one embodiment, the comparative comparison method includes at least parameter estimation and / or cross-correlation.

[0056] The measured signal of the operating variable can be compared with a model signal shape by a comparison method. The measured signal of the operating variable is determined so that it has a finite signal length that is substantially the same as the model signal shape. The comparison of the measured signal of the operating variable with the model signal shape can then be output, in particular as a discrete or continuous signal of finite length. Depending on the degree of agreement or discrepancy in the comparison, a result can be output regarding the work progress to be recognized, in particular whether an ideal impact without further rotation of the striking element is present or not.

[0057] In method step S4 of the method according to the invention, recognition of the work progress can be carried out at least partly with reference to the cross-correlation of the measured signals of the operating quantities with the model signal shape.

[0058] In another embodiment, the manual machine tool is an impact screwdriver, in particular a rotary impact screwdriver, and the work progress is the start or stop of a striking action, in particular a rotary striking action.

[0059] In particular, in method step S1, a model signal shape can be variably defined, in particular by a user, in which case a model signal shape is assigned to the work progress to be recognized, thereby allowing the user to set the work progress to be recognized.

[0060] Preferably, the model signal shape is predefined in method step S1, in particular on the factory side. In principle, it is conceivable that the model signal shape is stored or saved inside the tool, or alternatively and / or additionally provided to the manual machine tool, in particular provided by an external data device.

[0061] In another embodiment, the signals of the operating quantities are recorded in method step S2 as time progressions of the measured values ​​of the operating quantities or as measured values ​​of the operating quantities as electric motor quantities correlated with time progressions, for example acceleration, especially higher-order jerk, power, energy, the rotation angle of the electric motor, the rotation angle of the tool mount or frequency.

[0062] In the embodiment just mentioned, it is possible to ensure that the periodicity of the signal to be examined remains unchanged, regardless of the motor speed.

[0063] If the signals of the operating variables are recorded as time courses of the measured values ​​of the operating variables in method step S2, then in step S2a following method step S2, a conversion of the time courses of the measured values ​​of the operating variables into courses of the measured values ​​of the electric motor variables correlated with the time courses is carried out on the basis of a fixed transmission ratio of the transmission, thereby providing the same advantages as in the case of direct recording of the signals of the operating variables over time.

[0064] In this way, the method according to the invention allows the recognition of the work progress irrespective of at least one target speed of the electric motor, at least one starting characteristic of the electric motor and / or at least one state of charge of the energy supply of the manual machine tool, in particular of the accumulator.

[0065] The operating quantity signal is to be understood here as a time sequence of measured values. Alternatively and / or additionally, the operating quantity signal may be a frequency spectrum. Alternatively and / or additionally, the operating quantity signal may be post-processed, for example by smoothing, filtering, fitting, etc.

[0066] In another embodiment, the signals of the operating variables are stored as a series of measured values, in particular in a memory device of the manual machine tool, preferably in a ring buffer.

[0067] In one method step, the work progress to be recognized is identified with reference to fewer than 10 strikes of the striking mechanism of the manual machine tool, in particular with reference to fewer than 10 strike vibration periods of the electric motor, preferably with reference to fewer than 6 strikes of the striking mechanism of the manual machine tool, in particular with reference to fewer than 6 strike vibration periods of the electric motor, and most preferably with reference to fewer than 4 strikes of the striking mechanism, in particular with reference to fewer than 4 strike vibration periods of the electric motor. By strike of the striking mechanism, we mean strikes of the striking mechanism's striking part, in particular of the hammer, against the striking mechanism, in particular against the anvil, in the axial, radial, tangential, and / or circumferential direction. The strike vibration period of the electric motor is correlated with the operating variable of the electric motor. The strike vibration period of the electric motor can be determined with reference to operating variable fluctuations in the operating variable signal.

[0068] A further subject of the invention is a manual machine tool having an electric motor, a measurement recorder of the operating quantities of the electric motor, and a control unit, the manual machine tool being an impact screwdriver, in particular a rotary impact screwdriver, the manual machine tool being set up for carrying out the method described above.

[0069] The work progress to be recognized preferably corresponds to a strike without further rotation of the tool mount of the manual machine tool.

[0070] An electric motor of a manual machine tool rotates an input spindle, and an output spindle is connected to a tool mount. An anvil is non-rotatably connected to the output spindle, and a hammer is connected to the input spindle such that rotational movement of the input spindle results in intermittent axial movement of the input spindle and intermittent rotational movement about the input spindle, with the hammer intermittently striking the anvil and thereby outputting striking impulses and rotational impulses to the anvil and, therefore, the output spindle. A first sensor transmits a first signal to a control unit, for example, for determining the motor rotation angle. A second sensor transmits a second signal to the control unit for determining the motor speed.

[0071] The manual machine tool preferably has a memory unit in which various values ​​can be stored.

[0072] In another embodiment, the manual machine tool is a battery-operated manual machine tool, in particular a battery-operated rotary impact driver, thus ensuring a flexible and power-independent use of the manual machine tool.

[0073] The manual machine tool is preferably an impact screwdriver, in particular a rotary impact screwdriver, and the work progress to be recognized is preferably a strike of the rotary striking mechanism without further rotation of the struck element or tool mount.

[0074] The identification of the impact of the impact mechanism of a manual machine tool, in particular the impact vibration period of an electric motor, is carried out by, for example, to This can be achieved by applying a fitting algorithm, which allows for the assessment of impact recognition within a time period of less than 100 ms, in particular less than 60 ms, and very particularly less than 40 ms.The inventive method described above then allows for the recognition of work progress for practically all of the above-mentioned application cases and also for the screwing of loose as well as fixed fastening elements of the fastening carrier.

[0075] The present invention allows for a significant elimination of costly signal processing techniques such as filters, signal loopbacks, system models (static and adaptive), signal tracking, and the like.

[0076] In addition, these methods allow for faster recognition of impact movements or work progress, thereby resulting in faster tool responses. This is particularly true for the number of impacts that have elapsed since the start of the impact mechanism until recognition, and also applies in special operating situations, such as the start-up phase of the drive motor. This does not require restrictions on the functionality of the tool, such as reducing the maximum drive speed. Furthermore, the functioning of the algorithms is not dependent on other influencing variables, such as the target speed or the battery state.

[0077] Although in principle no additional sensor devices (e.g. acceleration sensors) are required, such an evaluation method can nevertheless also be applied to the signals of other sensor devices.Furthermore, such methods can also be applied to other signals in other motor concepts, for example without speed detection.

[0078] In one preferred embodiment, the manual machine tool is a battery driver, drill, percussion drill, or drill hammer, and can use drills, drill bits, or various bit attachments as tools. The manual machine tool according to the invention is particularly configured as an impact screwdriver, in which the impulsive release of motor energy generates a higher peak torque for screwing or unscrewing screws or screw nuts. Transmission of electrical energy in this context is intended to mean, in particular, that the manual machine tool transfers energy to the body via a battery and / or an electrical cable connection.

[0079] Furthermore, depending on the selected embodiment, the screw tightening tool can be configured to be rotationally flexible, so that the proposed method can be used both for screwing in and for unscrewing screws and threaded nuts.

[0080] Within the scope of the present invention, "determining" is intended to include in particular measuring or recording, "recording" is to be understood as meaning measuring and storing, and "determining" also includes possible signal processing of the measured signals.

[0081] Furthermore, "determining" is also to be understood as recognizing or detecting, so that an unambiguous assignment is achieved. "Identifying" is to be understood as the recognition of a partial match with a pattern, which may be made possible, for example, by fitting a signal to a pattern, by Fourier analysis, etc. A "partial match" is to be understood as the fitting having an error below a predetermined threshold, in particular below 30%, very in particular below 20%.

[0082] Other features, applicability, and advantages of the present invention will become apparent from the following description of an embodiment of the invention as illustrated in the drawings, in which it is to be noted that the features described or shown in the drawings, either by themselves or in any combination, constitute the subject matter of the present invention, regardless of their association or recitation in the claims, and regardless of how they are expressed or illustrated in the specification or drawings, are merely illustrative in nature and are not intended to limit the invention in any way.

[0083] The invention will now be described in more detail with reference to preferred embodiments. The drawings are schematic and show: [Brief explanation of the drawings]

[0084] [Figure 1] FIG. 1 is a schematic diagram showing an electric manual machine tool. [Figure 2a]This is a signal indicating the progress of the application and the corresponding operation amount. [Figure 2b] The signal of the operating quantity shown in Figure 2a matches the model signal. [Figure 3a] 1 is a schematic flow chart of the present invention based on the first embodiment. [Figure 3b] 4 is a schematic flow chart of the present invention according to a second embodiment. [Figure 4] There are two assigned signals: the work progress of the application example and the operating quantity. [Figure 5] 4 shows the progression of signals of operating quantities according to two embodiments of the present invention. [Figure 6] 4 shows the progression of signals of operating quantities according to two embodiments of the present invention. [Figure 7] There are two assigned signals: the work progress of the application example and the operating quantity. [Figure 8] 4 shows signal progressions of two operating quantities according to two embodiments of the invention; [Figure 9] 4 shows signal progressions of two operating quantities according to two embodiments of the invention; [Figure 10a] FIG. 1 is a schematic diagram showing two different recordings of signals of movement quantities. [Figure 10b] FIG. 1 is a schematic diagram showing two different recordings of signals of movement quantities. [Figure 11a] It is a signal of the amount of movement. [Figure 11b] 11b is an amplitude function of a first frequency contained in the signal of FIG. 11a; [Figure 11c] 11b is an amplitude function of a second frequency contained in the signal of FIG. 11a. [Figure 12a] 1 is a common diagram of the signal of the operating quantity and the output signal of the band-pass filtering based on the model signal. [Figure 12b] 1 is a common diagram of the signal of the operating quantity and the output signal of the band-pass filtering based on the model signal. [Figure 13a] 1 is a common diagram of the signal of the operating quantity and the output of the frequency analysis based on the model signal. [Figure 13b] 1 is a common diagram of the signal of the operating quantity and the output of the frequency analysis based on the model signal. [Figure 13c] 1 is a common diagram of the signal of the operating quantity and the output of the frequency analysis based on the model signal. [Figure 13d] 1 is a common diagram of the signal of the operating quantity and the output of the frequency analysis based on the model signal. [Figure 14a] 1 is a common diagram of signals of operating quantities and model signals for parameter estimation; [Figure 14b] 1 is a common diagram of signals of operating quantities and model signals for parameter estimation; [Figure 15a] 1 is a common diagram of a signal of an operating quantity and a model signal for cross-correlation; [Figure 15b] 1 is a common diagram of a signal of an operating quantity and a model signal for cross-correlation; [Figure 15c] 1 is a common diagram of a signal of an operating quantity and a model signal for cross-correlation; [Figure 15d] 1 is a common diagram of a signal of an operating quantity and a model signal for cross-correlation; [Figure 15e] 1 is a common diagram of a signal of an operating quantity and a model signal for cross-correlation; [Figure 15f] 1 is a common diagram of a signal of an operating quantity and a model signal for cross-correlation; [Figure 16a] 1 is a schematic flow chart of the present invention according to a first alternative embodiment; [Figure 16b] 4 is a schematic flow chart of the present invention according to a second alternative embodiment; [Figure 17] 3 shows signal progressions of two operating quantities according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0085] FIG. 1 shows a manual machine tool 100 according to the present invention, having a housing 105 with a hand grip 115. In the illustrated embodiment, the manual machine tool 100 can be mechanically and electrically coupled to a battery pack 190 for a power source-independent current supply. In FIG. 1, the manual machine tool 100 is exemplarily configured as a battery-powered rotary impact driver. However, it should be noted that the present invention is not limited to battery-powered rotary impact drivers, and in principle can be applied to any manual machine tool 100 that requires awareness of work progress, such as a perforator.

[0086] Arranged within the housing 105 are an electric motor 180, which can be supplied with current from a battery pack 190, and a transmission 170. The electric motor 180 is coupled to an input spindle via the transmission 170. Furthermore, a control unit 370 is arranged within the housing 105 in the region of the battery pack 190, which acts on the electric motor 180 and the transmission 170 to control and / or regulate them, for example by means of the adjusted motor speed n, the selected angular momentum, the desired transmission stage x, etc.

[0087] The electric motor 180 can be operated, i.e., turned on and off, for example, via a manual switch 195, and can be any motor type, such as an electronically commutated motor or a DC motor. In principle, the electric motor 180 can be electronically controlled so that it can implement settings for the desired motor speed n and the desired angular momentum, as well as reversing operation. The functional form and structure of suitable electric motors are sufficiently known in the art that, for the sake of brevity, a detailed description will not be given here.

[0088] A tool mount 140 is rotatably supported in the housing 105 through the input and output spindles. The tool mount 140 serves to receive a tool and may be integrally molded directly onto the output spindle or may be coupled thereto in the form of an attachment.

[0089] The control unit 370 is connected to a current source and is configured to electronically controllably excite the electric motor 180 with various current signals, which act on different angular momentum of the electric motor 180 and are sent to the electric motor 180 via control lines. The current source may be configured, for example, as a battery, or as a battery pack 190 in the illustrated embodiment, or as a power supply connection.

[0090] Furthermore, operating members, not shown in detail, may be provided to adjust the various operating modes and / or rotation directions of the electric motor 180 .

[0091] In one aspect of the present invention, a method for operating a manual machine tool 100 is provided, whereby the work progress of the manual machine tool 100, e.g., as shown in FIG. 1 , can be confirmed during application, e.g., during a screwing or unscrewing process, and as a result of such confirmation, a corresponding response or routine can be released on the machine side, thereby achieving a reliable, repeatable, and high-quality screwing or unscrewing process. Aspects of the method rely, inter alia, on examining signal shapes and determining a degree of agreement of the signal shapes, which can correspond to an evaluation of further rotation of a member, e.g., a screw, driven by the manual machine tool 100.

[0092] 2 shows in this respect an exemplary signal of the operating quantity 200 of the electric motor 180 of a rotary impact driver, which appears in this or a similar manner during a typical use of the rotary impact driver. The following description is directed to a rotary impact driver, but also applies in a corresponding manner within the scope of the present invention to other manual machine tools 100, such as, for example, a perforator.

[0093] On the horizontal axis x, time is plotted as a reference quantity in the present example of Fig. 2. However, in alternative embodiments, quantities that are correlated with time are plotted as reference quantities, such as, for example, the rotation angle of the tool mount 140, the rotation angle of the electric motor 180, acceleration, especially higher-order jerk, power, energy, etc. On the vertical axis f(x), the motor speed n applied at each point in time is plotted in this diagram. Instead of the motor speed, another operating quantity that is correlated with the motor speed can also be selected. In alternative embodiments of the invention, f(x) represents, for example, a signal of the motor current.

[0094] The motor speed and the motor current are operating variables that are normally detected by the control unit 370 in the manual machine tool 100 without any additional costs. The determination of the signal of the operating variable 200 of the electric motor 180 is indicated as method step S2 in Fig. 3, which shows a schematic flow chart of the method according to the present invention. In a preferred embodiment of the present invention, the user of the manual machine tool 100 can select on what operating variable the method of the present invention is to be performed.

[0095] Figure 2a shows the application of a loose attachment member, e.g., a screw 900, to an attachment carrier 902, e.g., a wooden board. As can be seen in Figure 2(a), the signal includes a first region 310 characterized by a monotonic increase in motor RPM and a region of relatively constant motor RPM, which can also be called a plateau. The intersection of the horizontal axis x and the vertical axis f(x) in Figure 2a corresponds to the start of the rotary impact driver during the screwdriving process.

[0096] In the first region 310, the screw 900 encounters a relatively low resistance in the mounting carrier 902, and the torque required for screwing is lower than the release torque of the rotary impact mechanism. That is, the progression of the motor rotation speed in the first region 310 corresponds to the operating state of the screwdriver without impact.

[0097] As can be seen in Figure 2a, in region 322, the head of screw 900 does not rest on mounting carrier 902, meaning that screw 900 driven by a rotary impact driver will rotate an additional rotation with each strike. This additional rotation angle may decrease as the work process progresses, which is reflected in the drawing by the shorter cycle time. Furthermore, the additional screwing may also be indicated by an average decreasing number of rotations.

[0098] When the head of the screw 900 subsequently reaches the base material 902, a higher torque and therefore more impact energy is required to further tighten the screw 900. However, because the manual machine tool 100 does not supply more impact energy, the screw 900 does not rotate any further, or only rotates a significantly smaller angle.

[0099] The rotary impact actions occurring in the second and third regions 322, 324 are characterized by an oscillatory profile of the signal of the operating variable 200, and the shape of the vibration can be, for example, trigonometric or other. In this example, the vibration has a profile that can be called a modified trigonometric function. Such a characteristic profile of the signal of the operating variable 200 in the impact screwdriving action is caused by the lifting and freewheeling motion of the striking part of the striking mechanism and the system linkage, particularly the transmission 170, between the striking mechanism and the electric motor 180.

[0100] That is, the qualitative signal shape of the impact operation is basically known based on the specific characteristics of the rotary impact driver. Based on this knowledge, in the method of Fig. 3a according to the present invention, comparison information is provided in step S1, which includes providing at least one state-typical model signal shape 240 in step S1a, which is assigned to a work progress, such as the reaching of the head of the screw 900 resting on the mounting carrier 902. In other words, the state-typical model signal shape 240 includes a typical indicator of the work progress, such as the presence of a vibration transition, a vibration frequency or vibration amplitude, or individual signal sequences with a continuous, quasi-continuous, or discrete shape.

[0101] In other applications, the work progress to be detected may be characterized by signal shapes other than oscillations, such as discontinuities or rate of increase in the function f(x). In such cases, the state-typical model signal shapes are characterized by these parameters instead of oscillations.

[0102] In a preferred embodiment of the method according to the invention, in method step S1a, a state-typical model signal shape 240 can be defined by a user. The state-typical model signal shape 240 can also be stored or saved internally in the tool. In alternative embodiments, the state-typical model signal shape can alternatively and / or additionally be provided to the manual machine tool 100, for example from an external data device. In another embodiment, the model signal shape 240 can also be selected and provided on the basis of coincidence signals, as will be explained later.

[0103] Additionally, the comparison information includes a match threshold provided in step S1b, which is described in more detail below.

[0104] In method step S3a of the method according to the invention, the signal of the operating variable 200 of the electric motor 180 is compared with a state-typical model signal shape 240, and a coincidence signal is determined from this comparison. The term "comparison" should be broadly interpreted in the context of the present invention in the sense of signal analysis, so that the result of the comparison may be a partial or gradual coincidence between the state-typical model signal shape 240 and the signal of the operating variable 200 of the electric motor 180, and the degree of coincidence of both signals can be determined by various mathematical methods, which will be mentioned later. In particular, the determination of the coincidence signal can include the determination of an error between the model signal and the signal of the operating variable, defined in an appropriate manner. In another embodiment, the determination of the coincidence signal can include the determination of a simple difference between the model signal and the signal of the operating variable.

[0105] The coincidence signal is evaluated in an automated manner according to the invention, as suggested by section AF of Fig. 3a, and is used to provide comparison information, i.e., to provide a model signal shape and / or a coincidence threshold, indicated by step S1b in Fig. 3a. In an embodiment of the invention, the automated evaluation of the coincidence signal comprises determining characteristics of the coincidence signal, in particular the slope, curvature, or local or global minimum or maximum of the coincidence signal. The notion of evaluation in this context is intended to include well-known means of curve approximation and the numerical methods used in this regard, in particular the calculation of numerical differentiation and integration.

[0106] In an embodiment of the present invention, the coincidence threshold is determined at least in part based on characteristics of the coincidence signal, for example when the coincidence signal falls below a certain slope as a time progression of the operating quantity of the electric motor or as a progression of the operating quantity correlated with time.

[0107] In certain embodiments, the matched signal is used as the basis for selecting and providing a new model signal shape 240 (see FIGS. 14b, 15b, 15e), thereby generating additional information obtained about the current screwdriving process.

[0108] In step S3b, the comparison further determines a match assessment between the state-typical model signal shape 240 and the signal of the operating quantity 200 of the electric motor 180, thus providing information about the match of both signals, the match assessment being performed at least in part with reference to a match threshold.

[0109] In a further particular embodiment, as shown in Fig. 3b, the coincidence assessment in step S3b is at least partly based on the frequency of the signals of the operating quantities. In this embodiment, in addition to the coincidence signal, the frequency of the rotational speed signal, measured for example during the percussion operation, is additionally measured, which is represented by the symbol SF in Fig. 3b. Since this frequency changes during the screwdriving process, the coincidence signal can be used to recognize the work progress of the manual machine tool, such as the end of the screwdriving case, and to release an appropriate motor response.

[0110] In the embodiment shown in FIG. 3b, the match assessment in step S3b is performed at least in part based on a logical operation, for example an "AND", "NAND" or "OR" operation, between the match signal and the frequency of the signal of the operating quantity.

[0111] In another embodiment, the coincidence assessment in step S3b is performed at least partly based on a sum signal of the coincidence signal and the frequency of the signal of the operating quantity.

[0112] In another embodiment, the match assessment in step S3b is based at least in part on fuzzy sets or membership functions (weighting functions), see fuzzy logic.

[0113] FIG. 2b shows the progression of the signal of the operating quantity 200 of FIG. 2a and the corresponding function q(x) of the agreement evaluation 201, where the value of agreement between the signal of the operating quantity 200 of the electric motor 180 and the state-typical model signal shape 240 is represented at each point on the horizontal axis x.

[0114] In the present example of the screwing in of a screw 900, such an evaluation is used to determine a measure of further rotation during the impact. The state-typical model signal shape 240 provided in step S1 corresponds in this example to an ideal impact without further rotation, i.e., the state in which the head of the screw 900 rests on the surface of the mounting carrier 902, as shown in region 324 of FIG. 2a. Accordingly, in region 324, a high degree of agreement between both signals occurs, as reflected by a consistently high value of the function q(x) of the agreement evaluation 201. In contrast, in region 310, where each impact involves a large rotation angle of the screw 900, only a low degree of agreement is obtained. The less further rotation of the screw 900 occurs with each impact, the higher this agreement becomes, as is evident from the fact that the function q(x) of the agreement evaluation 201 reflects a continuously increasing degree of agreement already upon the start of the impact mechanism in region 322, where the rotation angle of the screw 900 continues to decrease due to the increasing threading resistance with each impact.

[0115] In method step S4 of the method according to the invention, the work progress is then recognized at least in part with reference to the match score 201 determined in method step S3b. As can be seen from the example of Fig. 2, a match score 201 of the signal for impact discrimination based on more or less sudden features is well suited for this purpose, as this sudden change is due to a more or less sudden change in the further rotation angle of the screw 900 at the completion of the exemplary work process. The work progress can then be recognized at least in part with reference to a comparison of the match score 201 with a match threshold, for example, as indicated by the dashed line 202 in Fig. 2b. In the example of Fig. 2b, the intersection point SP of the function q(x) of the match score 201 with the line 202 is assigned to the work progress in which the head of the screw 900 rests on the surface of the mounting carrier 902.

[0116] That is, by distinguishing the signal shapes, the present invention allows for evaluation of further rotation of the member driven by the rotary impact driver to confirm the work progress of the application.

[0117] Despite the reduction in rotational speed that occurs when switching to a striking operation, it is extremely difficult to prevent the screw head from penetrating the material, for example in the case of small wood screws or self-tapping screws, because the striking of the striking mechanism results in high spindle rotations even when the torque is increasing.

[0118] Such behavior is shown in Figure 4. As in Figure 2, the horizontal axis x is plotted as an example with time, while the vertical axis f(x) is the motor speed and the vertical axis g(x) is the torque g(x). Graphs f and g therefore represent the progression of the motor speed f and torque g over time. The lower area of ​​Figure 4, again similar to the graph in Figure 2, shows a schematic representation of various states during the process of screwing wood screws 900, 900', and 900'' into mounting carrier 902.

[0119] In the operating state "no strike", designated in the drawing by reference numeral 310, the screw rotates with a high rotational speed f and a low torque g. In the operating state "strike", designated by reference numeral 320, the torque g rises sharply, while the rotational speed f only decreases slightly, as already mentioned above. Region 310' in Fig. 3 represents the region within which strike recognition takes place as described in connection with Fig. 2.

[0120] For example, in order to prevent the head of the screw 900 from getting stuck in the mounting carrier 902, according to the present invention, in method step S5 shown in FIG. 3a, an appropriate application-related tool routine or response is executed based at least in part on the work progress recognized in method step S4, such as switching off the machine, changing the speed of the electric motor 180, and / or providing optical, acoustic, and / or tactile feedback to the user of the manual machine tool 100.

[0121] In one embodiment of the present invention, the first routine comprises stopping the electric motor 180 taking into account at least one defined and / or configurable parameter, in particular configurable by the user of the manual machine tool.

[0122] 5 shows, as an example, a schematic illustration of an immediate tool stop after impact recognition 310′, thereby supporting the user in avoiding pinching of the screw head into the mounting carrier 902. In the drawing, this is indicated by the branch f′ of the graph f, which decreases sharply after region 310′.

[0123] One example of a defined and / or configurable parameter, particularly one that can be set by a user of the manual machine tool 100, is the time that the tool is stopped, as defined by the user, which is represented in FIG. 5 as time period T Stopp and by the associated branch f'' of graph f. In an ideal case, the manual machine tool 100 stops just when the screw head is flush with the screw-receiving surface. However, the time it takes for this to occur varies from application to application, so the time period T Stopp is preferably user definable.

[0124] Alternatively or additionally, in one embodiment of the invention, the first routine is intended to include a change, in particular a reduction and / or an increase, of the speed of the electric motor 180, in particular the target speed, and thus the spindle speed, after the hit is recognized. An embodiment in which a speed reduction is performed is shown in FIG. 6. Similarly, the manual machine tool 100 first operates in the operating state "no hit" 310, which is represented by the progression of the motor speed represented by the graph f. After the hit recognition in the region 310', the motor speed is reduced by a certain amplitude in this example, which is shown by the graphs f' to f''.

[0125] For the branch f'' of the graph f in Figure 6, Δ D6 , the amplitude, i.e., magnitude, of the change in the speed of the electric motor 180, indicated by , can be adjusted by the user in one embodiment of the present invention. By reducing the speed, the user has more time to react when the screw head approaches the surface of the mounting carrier 902. When the user considers that the screw head is sufficiently flush with the mounting surface, he can immediately stop the manual machine tool 100 using a switch. Compared to stopping the manual machine tool 100 after impact recognition, the change in the motor speed, or reduction in the example of FIG. 6 , has the advantage that the user's decision to switch it off makes this routine almost application-independent.

[0126] In one embodiment of the present invention, the amplitude Δ of the change in the rotation speed of the electric motor 180 D and / or the target value of the rotation speed of the electric motor 180 can be defined by the user of the manual machine tool 100, which further increases the flexibility of the routine in terms of its applicability for a wide variety of application cases.

[0127] In the embodiment of the present invention, the rotational speed of the electric motor 180 is changed multiple times and / or dynamically. In particular, it may be intended that the rotational speed of the electric motor 180 is changed in stages over time and / or along a characteristic curve of the rotational speed change and / or depending on the work progress of the manual machine tool 100.

[0128] Examples of this include, in particular, a combination of a speed reduction and a speed increase. Furthermore, the various routines or combinations thereof can be executed with a time offset relative to the recognition of a hit. The invention also encompasses embodiments in which a time offset between two or more routines is intended. For example, if the motor speed is reduced immediately after the recognition of a hit, the motor speed can be increased again after a certain time value. Furthermore, embodiments are contemplated in which not only the various routines themselves but also the time offset between each routine is set by a characteristic curve.

[0129] As mentioned at the beginning, the present invention includes an embodiment in which the work progress is characterized by a transition from the operating state "striking" of area 320 to the operating state "no striking" of area 310, which is clearly shown in FIG.

[0130] Such a transition of the operating state of the manual machine tool is given, for example, during the work progress in which the screw 900 is released from the mounting carrier 902, i.e., during the unscrewing process, which is shown diagrammatically in the lower region of Fig. 7. As in Fig. 4, in Fig. 7, the graph f represents the rotational speed of the electric motor 180, and the graph g represents the torque.

[0131] As already explained in connection with other embodiments of the present invention, the detection of characteristic signal shapes is also used here to detect the operating state of a manual machine tool, in this case the operating state of a striking mechanism.

[0132] In the "impact" operating state, i.e., region 320 in FIG. 7, the screw 900 does not rotate and a high torque g is applied. In other words, the spindle speed is equal to zero in this state. In the "no impact" operating state, i.e., region 310 in FIG. 7, the torque g decreases rapidly, which in turn causes the spindle motor speed f to increase rapidly. This sudden increase in the motor speed f, caused by the decrease in torque g after the screw 900 has come off the mounting carrier 902, often makes it difficult for the user to catch the loosened screw 900 or threaded nut and prevent it from falling.

[0133] The method according to the invention can be applied to prevent a threaded means, which may be a screw 900 or a nut, from being unscrewed so quickly that it falls off after it has been released from a mounting carrier 902. In this regard, reference is made to Figure 8, which substantially corresponds to Figure 7 in terms of the axes and graphs shown, and corresponding symbols indicate corresponding features.

[0134] In one embodiment, the routine includes, in step S5, stopping the manual tool 100 as soon as it is determined that the manual tool 100 is operating in the "no impact" operating mode, which is illustrated in Figure 8 by the branch f' of the motor speed graph f dropping sharply in region 310. In an alternative embodiment, the time T until the tool is stopped is Stopp can be defined by the user. In the drawing, this is shown by the branch f'' of the graph f of the motor rotation speed. As also shown in FIG. 7, after the transition from the region 320 (operating state "impact") to the region 310 (operating state "no impact"), the motor rotation speed first rises rapidly, and then, during the period T Stopp It will be apparent to those skilled in the art that the slope drops off sharply after .times.

[0135] Time Zone T Stopp If is appropriately selected, it is possible to reduce the motor speed to exactly "zero" when the screw 900 or nut is still in the screw hole. In this case, the user can remove the screw 900 or nut by turning it only a few times, or alternatively, leave it in the screw hole, for example to open the fastener.

[0136] Next, another embodiment of the present invention will be described with reference to Fig. 9. In this case, after the transition from region 320 (operating state "impact") to region 310 (operating state "no impact"), a reduction in the motor speed is carried out. The amplitude or magnitude of this reduction is represented in the figure by Δ D This reduction can be adjusted by the user in certain embodiments, in particular by specifying a target value for the rotational speed of the manual machine tool 100, which is located at the level of branch f' in FIG.

[0137] The reduction in motor speed and therefore spindle speed gives the user more time to react when the head of the screw 900 comes off the screw-receiving surface. When the user believes that the screw head or nut has been sufficiently tightened, the switch can be used to immediately stop the manual machine tool 100.

[0138] Compared to the embodiment described in connection with FIG. 8, in which the manual machine tool 100 is stopped immediately after the transition from region 320 (operating state "striking") to region 310 (operating state "no striking") or with a delay after the transition, the speed reduction has the advantage of being even more application-independent, since the user ultimately decides when the manual machine tool is switched off after the speed reduction. This can be advantageous, for example, in the case of long threaded rods, where there are applications in which, after loosening the threaded rod and the associated stopping of the striking mechanism, a more or less long unscrewing process must still be carried out. In other words, in these cases, the manual machine tool 100 is switched off after the stopping of the striking mechanism. Being rejected doesn't serve the purpose.

[0139] In some embodiments of the present invention, the progress of work is output to the user of the manual machine tool using an output device of the manual machine tool.

[0140] Next, some technical relationships and embodiments related to the implementation of method steps S1 to S4 will be described.

[0141] In a practical application, it may be intended that method steps S2, S3a and S3b are repeatedly performed during operation of the manual machine tool 100 in order to monitor the work progress of the application being performed. For this purpose, method step S2 may involve segmenting the determined signal of the operating quantity 200, so that method steps S2 and S3 are preferably always performed on signal segments of the same defined length.

[0142] For this purpose, the signals of the operating quantities 200 can be stored as sequences of measured values ​​in a memory device, preferably in a ring buffer. In this embodiment, the manual machine tool 100 comprises a memory device, preferably a ring buffer.

[0143] As already mentioned in connection with Fig. 2, in a preferred embodiment of the invention, in method step S2 the signal of the operating quantity 200 is determined as a time progression of the measured value of the operating quantity or as a measured value of the operating quantity as a quantity of the electric motor 180 correlated with the time progression, where the measured value can be discrete, quasi-continuous or continuous.

[0144] In this case, one embodiment provides that the signal of the operating quantity 200 is recorded as a time progression of the measured value of the operating quantity in method step S2, and that in method step S2a following method step S2, the time progression of the measured value of the operating quantity is converted into a time progression of the measured value of the operating quantity as a quantity of the electric motor 180 that is correlated with the time progression, such as, for example, the rotation angle of the tool mount 140, the motor rotation angle, acceleration, especially higher-order jerk, power, energy, etc.

[0145] The advantages of such an embodiment will now be explained with reference to Figure 10. Similar to Figure 2, Figure 10a shows the signal f(x) of the operating quantity 200 against the horizontal axis x, in this example against time t. As in Figure 2, the operating quantity may be the motor rotation speed or a parameter that is correlated with the motor rotation speed.

[0146] The diagram includes two signal profiles of operating variable 200, each of which may be assigned to one work step, i.e., for example, in the case of a rotary impact driver, to the rotary impact screwdriving mode. In both cases, the signals include wavelengths of vibration profiles which are ideally assumed to be sinusoidal, with the signal with the shorter wavelength T1 having a profile with a high impact frequency and the signal with the longer wavelength T2 having a profile with a low impact frequency.

[0147] Both of these signals can be generated by the same manual machine tool 100 at different motor speeds, depending in particular on what rotation speed the user requests from the manual machine tool 100 via the operating switches.

[0148] That is, if, for example, the parameter "wavelength" is to be used to define the state-typical model signal shape 240, then in this example at least two different wavelengths T1 and T2 must be stored as possible parts of the state-typical model signal shape, so that in both cases the comparison of the state-typical model signal shape 240 with the signal of the operating quantity 200 leads to the result "match". Since the motor rotation speed can generally vary over a wide range over time, this means that the wavelength to be searched for also changes, and therefore the method for recognizing such impact frequencies must also be adaptively adjusted accordingly.

[0149] With a large number of possible wavelengths, the process and programming costs would quickly rise commensurately.

[0150] Therefore, in a preferred embodiment, the time values ​​on the horizontal axis are converted into values ​​that correlate with time, such as acceleration, higher-order jerk values, power values, energy values, frequency values, rotation angle values ​​of the tool mount 140, rotation angle values ​​of the electric motor 180, etc. This is possible because the fixed transmission ratios from the electric motor 180 to the impact mechanism and to the tool mount 140 result in a direct and known dependence of the motor speed on the impact frequency. Such normalization results in a periodic vibration signal that remains unchanged and is independent of the motor speed, as is illustrated in Figure 10b by the signals resulting from the conversion of the signals corresponding to T1 and T2, where both signals have the same wavelength P1 = P2.

[0151] Accordingly, in this embodiment of the present invention, through time-correlated quantities such as tool mount 140 rotation angle, motor rotation angle, acceleration, and especially higher order jerk, power, energy, etc., the state-typical model signal shape 240 can be effectively defined for any rotation speed by just one parameter: wavelength.

[0152] In one preferred embodiment, the comparison of the signals of the operating quantities 200 in method step S3a is performed by a comparison method, which includes at least one frequency-based comparison method and / or a comparison-by-comparison method. The comparison method compares the signals of the operating quantities 200 with a state-typical model signal shape 240 whether at least a match threshold is met. The frequency-based comparison method includes at least band-pass filtering and / or frequency analysis. The comparison-by-comparison method includes at least parameter estimation and / or cross-correlation. The frequency-based comparison method and the comparison-by-comparison method are described in more detail below.

[0153] In an embodiment including band-pass filtering, the input signal, possibly converted into a time-correlated quantity as described above, is filtered through one or more band-pass filters whose passbands correspond to one or more state-typical model signal shapes. The passbands are derived from the state-typical model signal shape 240. It is also possible for the passbands to correspond to frequencies defined in relation to the state-typical model signal shape 240. If the amplitude of such frequencies exceeds a predefined limit value, as is the case when the work progress to be recognized is reached, the comparison in method step S3b results in the signal of the operating variable 200 being equal to the state-typical model signal shape 240 and therefore the work progress to be recognized has been reached. The definition of the amplitude limit value in this embodiment is understood as a determination of the correspondence between the signal of the operating variable 200 and the state-typical model signal shape 240, on the basis of which it is determined in method step S4 whether the work progress to be recognized exists.

[0154] An embodiment in which frequency analysis is applied as a frequency-based comparison method will be described with reference to Fig. 11. In this case, a signal of an operating quantity 200, which corresponds to the progression of the rotation speed of an electric motor 180 over time as an example, as shown in Fig. 11a, is converted from the time domain to the frequency domain with appropriate frequency weighting based on frequency analysis, for example, a Fast Fourier Transformation (FFT). Here, the concept of "time domain" in the above description can be understood not only as "the progression of an operating quantity over time" but also as "the progression of an operating quantity as a quantity correlated with time."

[0155] Frequency analysis in this manner is a well-known mathematical tool for signal analysis in many engineering fields, and has been applied in particular to approximating measured signals to various wavelengths as a series expansion of weighted periodic harmonic functions. For example, in Figures 11b and 11c, the weighting coefficients κ1(x) and κ2(x) as function progressions 203 and 204 over time indicate whether and how strongly a corresponding frequency or frequency band, not shown here for clarity of the drawings, is present in the progression of the examined signal, i.e., operating quantity 200.

[0156] That is, in the method according to the present invention, a frequency analysis can be used to determine whether the frequencies assigned to the state-typical model signal shape 240 are present in the signal of the operating quantity 200 and at what amplitude. In addition, it is also possible to define frequencies whose absence indicates the presence of a work progress that should be recognized. As mentioned in connection with band-pass filtering, it is possible to define amplitude limits that indicate the degree of match between the state-typical model signal shape 240 and the signal of the operating quantity 200.

[0157] For example, in the example of FIG. 11b, at time t2 (point SP2), the amplitude κ1(x) of a first frequency in the signal of operating variable 200, which is typically not found in state-typical model signal shape 240, falls below the associated limit value 203(a), which in this example is a necessary but not sufficient criterion for the presence of work progress to be recognized. At time t3 (point SP3), the amplitude κ2(x) of a second frequency in the signal of operating variable 200, which is typically found in state-typical model signal shape 240, exceeds the associated limit value 204(a). In a corresponding embodiment of the present invention, the common presence of amplitude functions κ1(x) and κ2(x) below or above limit values ​​203(a) and 204(a) serves as the primary criterion for assessing the correspondence between state-typical model signal shape 240 and the signal of operating variable 200. Accordingly, in this case, it is determined in method step S4 that the work progress to be recognized has been reached.

[0158] Alternative embodiments of the present invention utilize only one of these criteria, or a combination of one or both criteria with another criterion, such as electric motor 180 reaching a target RPM.

[0159] In an embodiment of the method of the present invention in which parameter estimation is used as a comparative comparison method, the measured signal of the operating quantity 200 is compared to the state-typical model signal shape 240, and estimated parameters for the state-typical model signal shape 240 are identified. The estimated parameters can be used to determine a measure of agreement between the state-typical model signal shape 240 and the measured signal of the operating quantity 200, with respect to whether the work progress to be recognized has been reached. Here, parameter estimation is based on a correction calculation, which is a mathematical optimization method well known to those skilled in the art. This mathematical optimization method allows the estimated parameters to be used to adjust the state-typical model signal shape 240 to a series of measurement data of the signal of the operating quantity 200. Depending on the measure of agreement between the state-typical model signal shape 240, parameterized by the estimated parameters, and a limit value, a determination can be made as to whether the work progress to be recognized has been reached.

[0160] The correction calculation of the parameter estimate comparison method can also be used to determine a measure of the agreement of the estimated parameters of the state-typical model signal shape 240 to the measured signal of the operating quantity 200 .

[0161] In one embodiment of the method according to the invention, the method of cross-correlation is used in method step S3 as a comparative comparison method. As with the mathematical method described above, the method of cross-correlation is also known per se to those skilled in the art. In the method of cross-correlation, a state-representative model signal shape 240 is correlated with the measured signal of the operating quantity 200.

[0162] Compared to the previously described method for parameter estimation, the result of the cross-correlation is again a signal sequence with a combined signal length consisting of the signal length of the operating variable 200 and the length of the state-typical model signal shape 240, which represents the similarity of the time-shifted input signals. The maximum value of this output sequence then represents the point of maximum agreement between both signals, i.e., the signal of the operating variable 200 and the signal of the state-typical model signal shape 240, and thus also serves as a measure of the correlation itself, which in this embodiment is used in method step S4 as a decision criterion for reaching the recognized work progress. The main difference from parameter estimation in the implementation of the method according to the invention is that for cross-correlation, any state-typical model signal shape can be used, whereas for parameter estimation, the state-typical model signal shape 240 must be representable by a parameterizable mathematical function.

[0163] FIG. 12 illustrates the measured signal of the operating quantity 200 when band-pass filtering is used as a frequency-based comparison method. Here, time, or a quantity correlated with time, is plotted as the horizontal axis x. FIG. 12a illustrates the measured signal of the operating quantity as an input signal for band-pass filtering, where in a first region 310, the manual machine tool 100 operates with a screwdriving motion. In a second region 320, the manual machine tool 100 operates with a rotary impact motion. FIG. 12b illustrates the output signal after the band-pass filter has filtered the input signal.

[0164] FIG. 13 illustrates the measured signal of the operating quantity 200 in a case where frequency analysis is used as a frequency-based comparison method. FIGS. 13a and 13b show a first region 310 in which the manual machine tool 100 is performing a screwdriving operation. The horizontal axis x of FIG. 13a plots time t or a quantity correlated with time. FIG. 13b shows a transformed version of the operating quantity 200 signal, which can be transformed from the time domain to the frequency domain, for example, by a fast Fourier transform. The horizontal axis x' of FIG. 13b exemplarily plots frequency f, thereby representing the amplitude of the operating quantity 200 signal. FIGS. 13c and 13d show a second region 320 in which the manual machine tool 100 is performing a rotary impact operation. FIG. 13c shows the measured signal of the operating quantity 200 plotted over the time of the rotary impact operation. FIG. 13d shows the transformed signal of the operating quantity 200, where the signal of the operating quantity 200 is plotted against frequency f on the horizontal axis x'. FIG. 13d illustrates a characteristic amplitude for the rotary impact operation.

[0165] 14 shows a typical case of comparison using the comparison method by comparing parameter estimates between the signal of the operating quantity 200 and the state-typical model signal shape 240 in the first region 310 described in FIG. 2. The state-typical model signal shape 240 has a substantially trigonometric curve, whereas the signal of the operating quantity 200 has a significantly different curve. Regardless of the selection of one of the comparison methods described above, the comparison between the state-typical model signal shape 240 and the signal of the operating quantity 200, performed in method step S3a in this case, results in a low degree of agreement between the two signals, so that the work progress that should be recognized in method step S4 is not recognized.

[0166] 14b shows a case where the desired work progress is achieved, and therefore there is a high degree of overall agreement between the state-typical model signal shape 240 and the signal of the operating quantity 200, even if discrepancies can be observed at individual measurement points. In this way, a comparison method based on a comparison of parameter estimates can be used to determine whether the desired work progress has been achieved.

[0167] FIG. 15 illustrates a comparison of the measured signal of the operating variable 200 (see FIGS. 15a and 15d) with a state-typical model signal shape 240 (see FIGS. 15b and 15e) using cross-correlation as a comparison method. In FIGS. 15a-f, time, or a quantity correlated with time, is plotted on the horizontal axis x. FIGS. 15a-c show a first region 310 corresponding to the screwdriving operation. FIGS. 15d-f show a third region 324 corresponding to the work progress to be recognized. As explained above, the measured signals of the operating variables in FIGS. 15a and 15d are correlated with the state-typical model signal shapes in FIGS. 15b and 15e. FIGS. 15c and 15f show the respective results of the correlation. In FIG. 15c, the correlation result within the first region 310 clearly shows a low agreement between the two signals. Therefore, in the example of FIG. 15c, it is determined in method step S4 that the work progress to be recognized has not been reached. Figure 15f shows the result of the correlation within the third region 324. As can be seen in Figure 15f, there is a high degree of agreement, which leads to a determination in method step S4 that the work progress to be recognized has been reached.

[0168] FIG. 16a shows a schematic flow chart of the invention according to a first alternative embodiment. The flow chart of FIG. 16a is distinguished from the flow chart described in FIG. 3a in that method step S1 is preceded by method step AM. In method step AM, the upper speed limit of the electric motor 180 is adjusted. The upper speed limit can be defined in the range of 20% to 100% of the maximum speed of the electric motor 180. In method step S5, the first routine comprises adjusting the rotational speed value of the electric motor 180 and keeping the rotational speed value substantially constant. Here, the rotational speed value for further screwing of the threaded element is kept substantially constant. Here, the rotational speed value is adjusted by the factory, but alternatively, the rotational speed value can also be adjusted by the user. Furthermore, method step S5 here comprises adjusting the time period T Stopp This includes being adjusted by the user.

[0169] 16b shows a schematic flow chart of the invention according to a second alternative embodiment. The flow chart of FIG. 16b is distinguished from the flow chart described in FIG. 3b in that method step S1 is preceded by method step AM. Here too, a first routine of method step S5 comprises adjusting the rotational speed of the electric motor 180 and keeping the rotational speed substantially constant. Furthermore, here too, a time period T Stopp is adjusted by the user.

[0170] 17 shows the progression of signals of two operation quantities according to one embodiment of the present invention. These progressions are divided into a region 310 of no impact, a region 310' of impact recognition, and a region 320 of impact movement. These progressions are plotted against time t. Here, the first coordinate represents the rotation speed n(t) of the electric motor 180. The first rotation speed graph n1(t) shows the progression of the rotation speed n(t) under the maximum rotation speed of the electric motor 180. Furthermore, for the first rotation speed graph n1(t), the progression of the rotation speed n(t) over the time period T Stopp is adjusted by the user. The second rotation speed graph n2(t) shows the progress of the rotation speed under the adjusted upper rotation speed limit. Here, the upper rotation speed limit is within the range of 20% to 100% of the maximum rotation speed of the electric motor 180. Here, the upper rotation speed limit is adjusted by the user. The second coordinate shows the thread prestress or the tightening torque F(t) of the screwdriver member that screws in. The first thread prestress graph F1(t) shows the progress of the thread prestress F(t) under the maximum rotation speed of the electric motor 180. The second thread prestress graph F2(t) shows the progress of the thread prestress F(t) under the adjusted upper rotation speed limit.

[0171] The invention is not limited to the embodiments described and shown, but rather includes all developments by one skilled in the art that come within the framework of the invention as defined by the claims.

[0172] Other embodiments are contemplated that may include further modifications and combinations of elements in addition to those described and illustrated. [Explanation of symbols]

[0173] 100 manual machine tools 180 electric motor 200 Operation amount 240 Model Signal Shapes 370 Control Unit

Claims

1. A method for operating a manual machine tool (100) having a striking mechanism, said manual machine tool (100) including an electric motor (180), said method comprising the following method steps: S1 comparison information is provided, including the following method steps S1a and S1b: S1a. at least one model signal shape (240) is provided, and the model signal shape (240) is assignable to a work progress of the manual machine tool (100), the work progress being a progress in the entire screwing or unscrewing process, and the work progress including starting or stopping the screw driving operation; S1b A threshold for matching is provided; S2: The signal of the operation amount (200) of the electric motor (180) is determined; S3: the signals of the comparison information and the operating quantities (200) are analyzed, which comprises the following method steps S3a and S3b, S3a. The signal of the operating quantity (200) is compared to the model signal shape (240) and a match signal is determined from the comparison, the match signal being the result of the signal comparison of the model signal shape (240) to the signal of the operating quantity (200); S3b. A match assessment is determined, the match assessment being performed at least in part with reference to a match threshold and with reference to a match signal; S4. The work progress is recognized at least in part with reference to the match assessment determined in method step S3; A method, wherein providing the comparison information is based at least in part on an automated evaluation of the matching signals, the automated evaluation of the matching signals including determining characteristics of the matching signals.

2. 2. The method of claim 1, wherein evaluating the coincidence signal comprises at least in part determining a slope of the coincidence signal.

3. 3. The method of claim 2, wherein the match threshold is determined at least in part based on a slope of the match signal.

4. 4. The method according to claim 1, wherein the match evaluation in method step S3b is performed at least partly with reference to the frequency of the signals of the operating quantities, preferably as a function of a frequency threshold.

5. 5. The method according to claim 4, wherein the coincidence evaluation in method step S3b is performed at least partly on the basis of a logic operation of the coincidence signals and the frequency of the signals of the operating quantities.

6. 6. The method according to claim 5, wherein the coincidence evaluation in method step S3b is performed at least partly on the basis of the sum of the coincidence signals and the frequency of the signals of the operating quantities.

7. 7. The method according to claim 1, wherein the operating quantity is the rotational speed of the electric motor (180) or is an operating quantity that is correlated with the rotational speed.

8. The method comprises the following steps: S5. A first routine of the manual machine tool (100) is executed based at least in part on the work progress recognized in method step S4; 8. The method according to any one of claims 1 to 7, characterized in that the first routine comprises a change, in particular a reduction and / or an increase, of the rotational speed of the electric motor (180).

9. 9. The method according to claim 8, wherein the amplitude of the change in the rotation speed of the electric motor (180) and / or the target value of the rotation speed of the electric motor (180) can be defined by a user of the manual machine tool (100).

10. 10. The method according to claim 8 or 9, characterized in that the speed of the electric motor (180) is changed multiple times and / or dynamically, in particular in a time-stepped manner and / or along a speed change characteristic curve and / or depending on the work progress of the manual machine tool (100).

11. 11. The method according to claim 8, wherein the first routine comprises adjusting a rotational speed value of the electric motor (180) and keeping the rotational speed value substantially constant.

12. The method comprises the following steps: S5. A first routine of the manual machine tool (100) is executed based at least in part on the work progress recognized in method step S4; 8. The method according to claim 1, wherein the first routine comprises adjusting a speed value of the electric motor (180) and keeping the speed value substantially constant.

13. 11. The method according to any one of claims 8 to 10, characterized in that the first routine and / or characteristic parameters of the first routine are adjustable and / or displayable by a user through application software ("App") or a user interface ("Human Machine Interface, "HMI"").

14. The method comprises the following steps: AM The upper limit of the rotation speed of the electric motor (180) is adjusted, Method step AM precedes method step S1 or follows other method steps S2 to S4, 14. The method according to any one of claims 1 to 13, characterized in that

15. 15. The method according to claim 1, wherein an output device of the manual machine tool is used to output the progress of the work to a user of the manual machine tool.

16. 16. The method according to claim 1, wherein the model signal shape (240) is an oscillatory transition, in particular a substantially trigonometric oscillatory transition.

17. 17. The method according to claim 1, wherein the signal of the operating quantity (200) is recorded in method step S2 as a time course of the measured value of the operating quantity or as a measured value of the operating quantity as a quantity of the electric motor (180) correlated with a time course.

18. 18. The method according to claim 1, wherein in method step S2, the signal of the operating variable (200) is recorded as a time course of the measured value of the operating variable, and in method step S2a following method step S2, a conversion of the time course of the measured value of the operating variable into a time course of the measured value of the operating variable as a quantity of the electric motor (180) correlated with the time course is carried out.

19. 19. The method according to any one of claims 1 to 18, characterized in that the comparison of the model signal shape with the signal of the operating quantity comprises at least one frequency-based comparison method and / or a comparative comparison method.

20. 20. The method according to any one of claims 1 to 19, characterized in that the manual machine tool (100) is an impact screwdriver, in particular a rotary impact screwdriver, and the work progress is the start or stop of a striking action, in particular a rotary striking action.

21. 20. A manual machine tool (100) comprising an electric motor (180), a recorder of measured values ​​of the operating quantities of the electric motor (180), and a control unit (370), characterized in that the control unit (370) is set up to perform the method according to any one of claims 1 to 19.

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