Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
  • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
  • B25F5/02—Construction of casings, bodies or handles
  • B25F5/021—Construction of casings, bodies or handles with guiding devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B23/00—Portable grinding machines, e.g. hand-guided; Accessories therefor
  • B24B23/04—Portable grinding machines, e.g. hand-guided; Accessories therefor with oscillating grinding tools; Accessories therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
  • B24B49/16—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the load
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
  • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S388/00—Electricity: motor control systems
  • Y10S388/935—Specific application:
  • Y10S388/937—Hand tool

Definitions

• the invention relates to electric hand tools and methods for operating management of electric hand tools.
• Electric hand tools are known, for example, as drills, drills, grinding machines and eccentric grinders. These electric hand tools generally have a rotatable tool holder for a tool. The tool holder is driven by an electric motor. Electric hand tools of simple design have specified a fixed speed for idling. Slightly better embodiments of the electric hand tools have the possibility that, depending on the application, a different speed can be adjusted. In electronically controlled electric hand tools this once set at idle speed during the work process, ie under load, kept constant. In the working process, the user presses the electric hand tool with his tool against the object to be processed. In an eccentric grinder, for example, a grinding substrate forming the tool is pressed against a workpiece to be ground.
• each user will apply a different pressure depending on their constitution and / or daily form during the work process.
• the work result varies depending on the pressure applied.
• the grinding quality that is to say the surface quality of the workpiece after grinding, will have different qualities for grinding operations which were carried out with different contact pressures.
• the material removal rate varies depending on the contact pressure. The probability is very high that the contact pressure during the duration of a work process is not kept constant by the user and thus the work process is not g is carried out moderately. Furthermore, it is desirable to reproducibly apply the contact pressure, that is, to resume it at the same contact pressure when the work process is interrupted.
• the electric hand tool according to the invention with an electric motor serving to drive a tool is characterized in that a sensor unit which detects the contact pressure of the tool on a workpiece cooperates with a signal generator.
• a sensor unit which detects the contact pressure of the tool on a workpiece cooperates with a signal generator.
• the fact that the applied contact pressure is visible to the user by means of the signal generator he can determine whether he exerts a contact pressure in an optimized work area.
• the optimized workspace ensures excellent work results. If the contact pressure is above the contact pressure of the optimized working range, the user can reduce the contact pressure due to the feedback from the signal generator. On the other hand, if too low a value for the applied contact pressure is displayed, the user can increase the contact pressure.
• the feedback by the signal generator can also be made such that it is indicated whether the value of the contact pressure during the working process is kept constant or whether the user changes it unintentionally.
• the electric hand tool according to the invention it is thus possible to monitor the contact pressure and by appropriate measures of the user this during a working pro to keep it at a suitable level, in particular constant. Furthermore, the requirement is created by the electric hand tool according to the invention that a working process is continued after an interruption with the same contact pressure.
• the electric hand tool has an electric motor which serves to drive a tool and a control and / or regulating unit which serves to guide the operation of the electric motor and which with the sensor unit controls the contact pressure of the tool on the workpiece recorded, interacts.
• the control and / or regulating unit is thus able to adjust the operation of the electric motor to the currently applied by the user contact pressure.
• the quality of the work result achievable with an electric hand tool is determined by several working parameters. These working parameters include the contact pressure and operating parameters influenced by the electric motor, such as the torque and the rotational speed of the tool. In order to carry out an optimized work process, it is necessary to coordinate these working parameters.
• the prerequisite is created that by means of the control and / or regulating unit the optimized working parameters of torque and / or rotational speed associated with the currently applied contact pressure are set.
• the user of the electric hand tool can thus devote himself to the working process, for example the grinding or drilling process, with full concentration and nevertheless has the certainty that the working process takes place in the optimal working range, at least with regard to the detected / measured variables.
• the control and / or regulating unit reacts by readjusting, for example, the torque, so that the working process remains in the desirable range and an optimum work result is achieved.
• the electric hand tool is characterized in that the sensor unit has a strain gauge and / or a piezoelectric sensor. This allows a direct measurement of the contact pressure of the tool on the workpiece. Furthermore, the contact pressure can be measured very precisely. In addition, these sensors have a small size. This allows them to be easily integrated into the electric hand tool.
• the electric hand tool is characterized in that the sensor unit has a current measuring device which measures the motor current of the electric motor. From the respective motor current of the applied pressure applied at this time can be derived. Under load, a certain torque will set, which depends on the motor current. As long as the electric motor is not saturated, which may be idle in particular, the torque is proportional to the square of the motor current. On the other hand, when the electric motor is operating in saturation due to a load, the torque is substantially proportional to the motor current. If the contact pressure is increased, the motor current of the electric motor will increase. If the contact pressure is lowered, the motor current will be lower. Thus, by determining the motor current, the contact pressure can be determined by relative determination. This is advantageous because it is a cost-effective way to determine the contact pressure, without any structural changes (as necessary for force sensors) are made to the electric hand tool.
• the electric hand tool has a current measuring device, which encompasses a shunt through which the motor current flows and an evaluation electronics.
• the current measurement by means of a shunt is very precise. It is measured the dropped voltage at the shunt, which by means of known resistance value of the shunt in the transmitter is converted into a current value or a statement about the contact pressure.
• the signal transmitter is an optical and / or acoustic and / or touch sensor responsive to the sense of touch. It is advantageous to provide transducers that address different senses of a user, since the electric hand tools are used in different work environments. For example, it may be advantageous to use an optical sensor or a touch sensor responsive to a sense of touch in a loud working environment, and not an acoustic signal generator. In a work environment with many visual stimuli or when the work process requires close observation of the user's work process, it may be better to use an audible signaler.
• the optical signal transmitter includes at least one LED and / or an LED array and / or a display and / or a bar graph.
• the said optical signal transmitters have a low energy consumption and are of small physical form. LEDs can be used in different color versions and thus allow a differentiated statement of the contact pressure with the color of color transitions, the "on / off" function and / or the variation of brightness By means of bar displays not only the momentary value of the contact pressure can be indicated, but also a trend statement. If the desired contact pressure, for example, in the middle of the bar display, so it can be too large or too small contact pressure due to significant display deviation from the Simply determine center.
• an electric hand tool with an acoustic signal generator which is a speaker and / or a bell and / or a buzzer or the like.
• Acoustic signals such as ringing tones or tones emitted by a loudspeaker are possible as signal symbols.
• signal symbols Preferably, they are used so that when the signal sounds, this indicates to the user that he is working in handling the electric hand tool in a non-optimized work area. It is also possible to vary the pitch with the contact pressure deviation, so that the user can orient himself very easily.
• the loudspeaker is assigned a device having a voice output. It is advantageous, for example, here that in addition to a simple signal in addition to linguistic information, such as work instructions for the user, can be output.
• control and / or regulating unit controls and / or regulates the torque of the tool, or a tool holder, as a function of the contact pressure of the tool on the workpiece.
• a load is exerted on the tool that results from the interaction of the tool with the workpiece.
• the drive / electric motor is loaded due to the friction between the grinding surface and the surface of the workpiece. The load depends on the contact pressure and increases when a larger contact pressure is exerted.
• the deceleration causes a reduction in the rotational speed of the tool and at the same time an increase in the torque.
• the electric hand tool controls and / or regulates the rotational speed of the tool, or of the tool holder, depending on the contact pressure of the tool on the workpiece by means of the control and / or regulating unit.
• the speed of a tool is generally lowered under load.
• it is important to work at a certain speed for a good work result.
• it is advantageous to control the speed of the tool as a function of the contact pressure and / or to regulate, for example, to keep it constant.
• control and / or regulating unit controls and / or regulates the torque of the tool or of the tool holder as a function of the contact pressure of the tool on the workpiece at a predetermined speed.
• the speed set by the user at the beginning of the work process is kept constant.
• the torque of the parameters of the applied pressure is automatically adjusted.
• the contact pressure of the tool automatically becomes apparent in a first step determines the workpiece to provide in the next step by the output of the contact pressure a possibility for the user to change the same. It is advantageous that the user who works with the electric hand tool, is supported in handling. This means with support that during the entire work process he receives feedback about whether he is applying the contact pressure in the optimized work area and / or whether he is keeping it constant. He is able to change the contact pressure on the basis of the feedback from the signal generator and receives feedback on whether the change was sufficient. If he has changed the contact pressure unintentionally, he gets this displayed and can track this. For example, if a bar graph is used as the signal generator, the user merely has to make sure that the displayed value for the contact pressure he exerts remains in the correct area of the display field. He sees immediately when he changes the contact pressure and can react.
• FIG. 1 a schematic view of an electric hand tool designed as an eccentric sander with sensor unit and signal generator;
• FIGS. 2 to 6 show examples of different displays of an optical signal transmitter
• FIG. 7 shows an electric hand tool designed as an eccentric sander with sensor unit and control and / or regulating unit
• FIG. 9 shows a flow chart of a method for operating an electric hand tool
• FIG. 10 shows a flowchart of a method for the automatic operation of an electric hand tool.
• FIG. 1 shows an electric hand tool 1, which is designed as an eccentric grinder. It has a housing 2, an electrical supply cable 3 and a handle 4. Furthermore, FIG. 1 shows a tool holder 6 'with a tool 6, with which a workpiece 7 is machinable. The drive of the tool 6 takes place with an electric motor 8. The operating during operation at a certain speed and a corresponding torque electric motor 8 drives the trained as an abrasive substrate tool 6 at. Depending on the embodiment of the electric power tool 1, either a fixed speed is predetermined or different values for the speed can be set. With the electronically controlled electric hand tools, the speed set once during the work process, ie under load, is kept constant.
• a sensor unit 9 determines the contact pressure of the tool 6 applied by the user when handling the electric power tool 1 on the workpiece 7.
• the sensor unit 9 has a strain gauge, not shown in the figure or - in an alternative embodiment - a piezoelectric sensor. It may also, as described in more detail in Figure 8, a current measuring device 23 for measuring the motor current of the electric motor 8 have. For a description of the current measuring device 23 of the sensor unit 9, reference is made to the description of FIG.
• the sensor unit 9 interacts with a signal transmitter 10 via an electrical connection 11.
• the signal generator 10 may be an optical signal transmitter 12 and / or an acoustic signal transmitter 13.
• the signal generator is a signal sensor 14 which is responsive to the sense of touch and which acts vibrie- rend on the handle 4 to give the user a signal.
• the acoustic signal generator 13 may be formed as a bell, buzzer or speaker. In particular, it is possible to associate the speaker with a device for a voice output. All three embodiments of the signal generator 10 may be provided both alternatively and in different combinations.
• the sensor unit 9 determines the applied pressure applied by the user of the tool 6 on the workpiece 7 and reports the corresponding value to the signal generator 10, which conveys to the user information about the size of the contact pressure. If the user exerts too small a contact pressure, he receives via the signal generator 10 the information to increase the contact pressure. If its applied contact pressure is too great, it also receives a corresponding signal from the sensor unit 9, so that it can reduce the contact pressure in order to be able to apply the correct contact pressure required for the grinding process in this manner.
• optical signal transmitters 12 are shown in FIGS.
• the optical signal transmitter 12 -according to FIG. 2 - is in the simplest case a light-emitting diode 15 (LED) with e.g. green color. If the value determined for the contact pressure is in the optimized operating range, the optical signal transmitter lights up. If the contact pressure in the optimized working range is exceeded or undershot, the LED goes off. This is how the user is shown when he applies the pressure in the optimized working area. However, it is also conceivable that the LED may be of e.g. is red LED and the logic of the display of the optical signal transmitter 12 is such that only at a contact pressure, which is not in the optimized working range, the LED lights up.
• LED light-emitting diode 15
• the user is shown when he applies a contact pressure, which is not in the optimized working area. Additionally or alternatively, it is possible to vary the brightness of the LED to signal the respective contact pressure. It is also conceivable that the LED flashes in the event of deviation from the contact pressure of the optimized operating range. If the contact pressure is increased, the flashing frequency increases; if it is lowered, the flashing frequency decreases.
• the optical signal transmitter 12 has two LEDs 16, which allow a more sophisticated statement.
• An LED is one red LED and the other LED is a green LED. If the contact pressure is in the optimized working range, the green LED lights up. If the contact pressure outside the optimized working range, the red LED lights up. If the contact pressure changes, but is still in the optimized range, the red LED lights up in addition to the green LED. If the contact pressure is no longer in the optimized working range, the green LED goes off and only the red LED lights up.
• the LED array 17 consists of a plurality of light-emitting diodes 16 arranged in a row.
• the middle LED lights up when the contact pressure, e.g. has a value in the optimized range at the beginning of the work process. If an LED to the right of the middle LED illuminates, this means that the value for the contact pressure is higher than the optimum value. The further the contact pressure is away from the optimal value, the farther the luminous LED is from the center. Likewise, a glowing LED to the left of the middle LED means that the user is exerting too little pressure. Thus, the user is additionally shown the type of deviation (too high or too low contact pressure) and the size of the deviation from the optimized value. It is also possible to construct an LED array 17 of LEDs of different colors and to realize statements in this way. Of course, the LED panel 17 may be constructed of two or more rows.
• the statement of a bar display 18, as shown in FIG. 5, is analogous to the statement of the LED field 17.
• the height of the contact pressure is indicated by means of the length of the bar.
• the optical signal transmitter 12 is a display 19, as shown in FIG. 6, the value of the contact pressure is displayed and indicated by the "Greater” symbol. or “small” symbols indicate an overshoot or undershoot of the optimized value for the contact pressure.
• optical signal transmitter 12 It is also possible to combine the various optical signal transmitters 12.
• An example would be the combination of e.g. red LED 15 with a display field.
• the LED indicates when the contact pressure is not in the optimized range and the display 19 indicates the specific value.
• the illustrated embodiments for the optical signal transmitter 12 are to be understood merely as examples.
• the electric hand tool according to the invention may also comprise other embodiments for the optical indication of the contact pressure.
• the optical signal transmitter 12 is combined with the acoustic signal transmitter 13.
• a e.g. Green LED illuminates when the contact pressure is optimized and when the contact pressure is exceeded or undershot, an acoustic signal sounds and the LED goes out.
• FIG. 7 shows an electric hand tool 1 designed as an eccentric sander.
• the same parts are provided with the same reference numerals as in Figure 1 and reference is made to the description of Figure 1.
• a control and / or regulating unit 20 is present, which cooperates with the electric motor 8.
• the contact pressure determined with the sensor unit 9 is supplied to the control and / or regulating unit 20 by means of an electrical connecting line 21.
• An electrical connection 22 establishes an electrical contact between the control and / or regulating unit 20 and the electric motor 8.
• the contact pressure is by means of Sensor unit 9 determined and transmitted to the control and / or regulating unit 20. This interacts with the electric motor 8 and changes its parameters, ie the torque and / or the rotational speed such that the rotational speed and / or the torque fits this contact pressure and the eccentric sander operates in an optimized operating range.
• Working in an optimized work area leads to a good work result and to an optimized working time.
• the tool 6 of the drill driver is a bit with which a screw is screwed into a workpiece 7.
• An optimized working range for a drill screwdriver is characterized by the fact that the bit does not spin, so does not slip over the cross slot of the screw.
• a specific torque will be set depending in particular on the screw and the workpiece. If the user-imposed contact pressure for a specific torque is too low, the bit rotates and screwing in the screw is no longer possible. The flanks of the Phillips are damaged.
• the sensor unit 9 determines the contact pressure that is displayed to the user by the signal generator 10.
• a drill driver with a control and / or regulating unit 20 is used, which cooperates with the electric motor 8 and the torque and / or the speed controls or regulates. This means, in particular, that only a torque, which lies within a limited range of values, is delivered to a specific contact pressure. This makes it possible to avoid slipping / over-turning of the bit in the screw cross slot.
• the current measuring device 23 has the task of determining the motor current flowing through the electric motor 8 and from this the contact pressure which a user exerts on the tool 6 or on the tool holder 6 ', respectively.
• the operation of the current measuring device 23 is as follows: At the shunt 31 occurs by the motor current to the resistance of the shunt 31 proportional voltage drop, so that between the terminal 32 and the terminal 33, a voltage difference. This voltage difference is converted in the evaluation unit 36 into a value which corresponds to the contact pressure. This procedure is possible due to the following circumstances: A contact pressure exerted on the tool 6 or the tool holder 6 'results in a specific torque being set. The torque of the electric motor is approximately proportional to the motor current in the normally present saturation mode.
• FIG. 9 shows, as a flowchart, a method for the operation of an electric hand tool 1 with sensor unit 9 and signal generator 10 -as shown in FIG.
• the first method step 40 includes the determination of the contact pressure with which the user presses the tool 6 of the electric power tool 1 onto the workpiece 7 to be machined.
• the determined value for the contact pressure is - indicated at 42 - supplied to the second method step 41.
• the user is made aware of whether the determined value of the contact pressure is within an optimized working range.
• electric hand tool 1 is stored in a memory, which contact pressure for the performance of work in the optimized work area must be applied in each case. In that regard, the electric hand tool 1 is able to guide the user automatically.
• the user receives by the invention a classification / assessment of the pressure exerted by him.
• the action of the user is shown in Figure 3 by a line 43 representing feedback. It can be provided that this feedback process is continuous, that is continuous or at certain time intervals.
• FIG. 10 shows, as a flowchart, a method for the operation of an electric hand tool 1 with sensor unit 9 and control and / or regulating unit 20-as shown in FIG.
• the contact pressure determined in method step 40 is transmitted to a second method step 44, corresponding to line 42.
• this value is stored in the electric hand tool 1 optimal working parameters of the Electric motor 8 related.
• a control and / or regulation instruction 45 of the control and / or regulating unit 20 is given to the electric motor 8 in accordance with a third method step 46. This adjusts its speed and / or its torque automatically to the effect that the electric hand tool works in the optimized working area.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

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• 2004
  • 2004-01-22 DE DE102004003203A patent/DE102004003203A1/de not_active Withdrawn
  • 2004-11-23 WO PCT/DE2004/002582 patent/WO2005070624A1/de active Application Filing
  • 2004-11-23 CN CNA2004800408227A patent/CN1905995A/zh active Pending
  • 2004-11-23 EP EP04802793A patent/EP1715983A1/de not_active Ceased
  • 2004-11-23 US US10/561,312 patent/US7504791B2/en not_active Expired - Fee Related
  • 2004-11-23 JP JP2006549847A patent/JP2007518582A/ja active Pending

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