EP0303651A1

EP0303651A1 - Process for interrupting the operation of a hand tool, in particular percussion and/or rotation thereof.

Info

Publication number: EP0303651A1
Application number: EP19880901798
Authority: EP
Inventors: Wolfgang Schmid; Ludwig Thome; Karl Wanner
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1987-03-05
Filing date: 1988-03-02
Publication date: 1989-02-22
Anticipated expiration: 2008-03-02
Also published as: WO1988006508A2; EP0303651B1; EP0303651B2; DE3884522D1; WO1988006508A3

Abstract

Un procédé permet de mettre hors circuit pendant la marche à vide un marteau perforateur et/ou un trépan à tranchement. Un embrayage (28) agencé au moins dans la chaîne cinématique de percussion est automatiquement désengagé lorsque le point mort est atteint. Le moment où l'outil (24) atteint une position située sur la course de marche à vide est détecté et l'embrayage (28) est automatiquement désengagé lorsque cette position est atteinte et enclenché à nouveau lorsque l'outil quitte cette position. A cet effet, un détecteur de marche à vide (30) provoque électromécaniquement l'engagement et le désengagement de l'embrayage (28) par l'intermédiaire d'un dispositif de commande (34). L'ouvrier maniant le marteau perforateur n'a donc pas besoin d'exercer d'efforts supplémentaires d'actionnement ou d'embrayage afin de mettre en et hors circuit l'outil à percussion, ce qui réduit le temps de marche à vide.A method makes it possible to switch off a rotary hammer and / or a trench bit during idling. A clutch (28) arranged at least in the percussion kinematic chain is automatically disengaged when neutral is reached. The moment when the tool (24) reaches a position on the idle run is detected and the clutch (28) is automatically disengaged when this position is reached and engaged again when the tool leaves this position. To this end, an idling detector (30) electromechanically causes the engagement and disengagement of the clutch (28) via a control device (34). The worker handling the hammer drill therefore does not need to exert additional actuation or clutch forces in order to switch the impact tool on and off, thereby reducing the idling time.

Description

Method for interrupting the drive activity, in particular the impact and / or rotary drive activity, of a hand tool

State of the art

The invention relates to a method for interrupting the drive activity of a hand tool according to the preamble of claim 1 or 9. It is known (DE-PS 2449191) to arrange a non-positive clutch in the form of a cone clutch in the drive train of the striking mechanism alone, which normally disengages and separates the striking mechanism from the drive train. However, if the operator presses the hand tool against the rock, the tool holder is moved backwards into the hand tool via the tool. This displacement movement is used via a displacement of the rotary sleeve serving for the rotary drive for the axial displacement of the driven shaft, as a result of which the cone coupling half, which is non-rotatable thereon, is pressed axially against another cone coupling half of the striking mechanism and so, when the coupling is engaged, the striking mechanism is now also driven. The clutch is thus automatically engaged depending on a force that the operator has to apply by firmly pressing the handheld power tool. This makes handling difficult. In addition, relatively large idling distances must be provided on the machine side, which is not only impractical for handling, but also increases the axial length. Furthermore, it is known (DE-PS 28 20 128) to arrange a safety clutch as a clutch in the drive train, which responds when a certain transmitted torque is reached and then separates the pressure drive. Such safety clutches are designed, for example, as slip clutches, friction clutches or releasable clutches. Such safety clutches respond depending on the force. This works well if the user of the hand-held machine tool is prepared for the moment that suddenly occurs in the event of a blockage and the hand-held machine tool keeps holding the corresponding counter-moment in anticipation of this malfunction. However, these prerequisites are often not met, so that, for example, twisted or even injured wrists and arms repeatedly occur with the user of such hand-held power tools, in particular rotary hammers. As a preventive measure, on the other hand, it is also known to set the response torque of such described safety clutches lower, with the result that, with larger drill diameters or longer drilling, the torque required for working is not achieved and the safety clutch constantly responds. In a disadvantageous way, the performance of the handheld power tool cannot be fully utilized. Even adjustable safety clutches do not bring a satisfactory solution. You can work in the upper torque range, but you have to expect a correspondingly greater torque surge in the event of a lock.

It is also known (DE-OS 35 11 437) to arrange force measuring elements within the hand-held power tool for the reasons mentioned, which react when a predetermined torque is reached and generate a signal. This is intended to serve in a non-resolved manner for the generation of control functions and is example for switching off the energy supply, for actuating one Clutch or brake and the like can be used. Piezo-ceramic ones are addressed as force measuring elements. Even with this known method, one is arrested in the idea that force-dependent variables are used as overload variables for automatically disengaging a clutch, for example, as in the described safety clutches. However, this does not eliminate the disadvantages described above.

Advantages of the invention

The method according to the invention with the characterizing features of claim 1 has the following advantages. Since the reaching of a travel position of the tool or a translationally moving part of the striking mechanism located on the idling distance is recorded as the variable and the clutch is automatically disengaged when this travel position is reached and automatically engaged when leaving this travel position, there is an automatic idling shutdown or automatic restart, without the user of the hand power tool having to apply any additional operating forces or, in particular, engagement forces. Rather, the disengagement of the clutch depends solely on the displacement of the tool forward into the idle position, just as the engagement of the clutch depends solely on the tool being moved from this idle position to the rear in the position corresponding to the striking operation. The user can therefore work loosely and relaxed, without having to constantly apply special pressing forces to maintain the percussion drive. The handling of the hand machine tool is considerably simplified. Greater ease of use is achieved. It is also advantageous that any other idling devices or catch devices are dispensable and the method according to the invention makes it possible to have almost any short idling distances. The idle travel can thus be significantly reduced, which leads to faster response and to more direct operation of the hand tool. Depending on the construction of the hand-held power tool, a reduction in the axial length in the axial direction of the tool holder is also possible. Furthermore, the prerequisites are created to simplify the coupling, if necessary, since one does not necessarily have to rely on a cone coupling with cone halves that can be pressed axially against one another.

In addition, the following advantages can be achieved with the method according to the invention with the characterizing features of claim 9. As a size - here as an overload size - a movement size of the hand-held craft machine in the hem is detected, the z. B. can consist of a path and / or a speed and / or an acceleration, and since the clutch is automatically disengaged when a predetermined value of such a movement size is exceeded, there is always the same safety for the user of the hand tool, regardless of the drive torque Hand tool that the user applies with the holding torque. The user does not need to have a holding moment that is far too large for most of the time in anticipation of blocking. Rather, he can work loosely and relaxed, without fear of being surprised by a sudden blockage and, for example, in the case of a rotary hammer during drilling operation by throwing the rotary hammer around when the drill is blocked, e.g. snagging of the drill in stone, concrete or the like. to get hurt. The invention is based on the basic etching knowledge that the swiveling movement of the hand-held machine tool, in particular a rotary hammer, which occurs when a rotating tool is blocked, itself as a signal for the interruption of the drive activity, in particular rotary drive activity, and not about a force-dependent quantity, for example a torque, in the Power flow of the rotary drive. As soon as, for example, a certain swivel movement that is still permissible for the hand holding the hand machine tool, for example in the order of magnitude of 10 ° in a maximum time, is exceeded, the clutch is disengaged and the drive activity is interrupted. It is irrelevant how firmly the user holds the hand tool and how stable he is. Because of the method according to the invention, care is reliably taken, regardless of this, that inadmissible pivoting movements of the handheld power tool and the hand holding it are prevented with all the known impairments and damage resulting therefrom.

Of course, the advantages achieved with the means of claim 9 can also be achieved independently of the means of claim 1.

Advantageous further developments and improvements of the method specified in the main claim are possible due to the features contained in the further claims. The invention further relates to a hand tool with the features in the preamble of claim 21. According to the invention, such a hand tool is characterized by the features in the characterizing part of claim 21. Advantageous further developments and improvements of such a hand-held power tool result from the features in claims 22-41. The hand-held power tool designed in this way is relatively simple in construction and inexpensive. Since it has the advantages explained at the outset, this justifies the overall little additional effort, also with regard to the reliable safety achieved and easier handling for the user.

drawing

The invention is explained in more detail below with reference to exemplary embodiments shown in the drawings. Show it:

1 is a schematic, partial axial longitudinal section of a hand power tool, in which only a few important parts of the drive train are shown in simplified form;

2 shows a simplified schematic functional diagram,

Fig. 3 is a schematic representation of the

Translation path of a tool driven by means of the hand tool according to FIG. 1,

Fig. 4 is a simplified schematic functional diagram.

Fig. 5 is a schematic, partial axial

Longitudinal section of a hand tool, at which shows simplified only some important parts of the drive train,

6 and 7 each simplified schematic functional diagrams of different modes of operation of the hand machine tool in Fig. 1,

8 is a schematic side view of a clutch in the disengaged state,

9 and 10 is a schematic side view and front view of the clutch in the engaged state,

11 shows two further exemplary embodiments of a hand tool and 12 machine according to FIG. Fig. 1.

Description of the invention

In Fig. 1, a hand tool is shown schematically, which here consists of a hammer drill or which can instead consist of a pure hammer for chisel operation. Such hammers are generally known (DE-AS 12 06 817). The hammer drill shown has a housing 10 in which an electric drive motor 11, which is designed as a universal motor, a gear 12 and a striking mechanism 13 are arranged. The hammer drill is e.g. designed in accordance with DE-OS 28 20 128, to which express reference is made here, so that particular details of the transmission 12 and the striking mechanism 13 do not have to be explained in detail.

The drive motor 11 carries on the motor shaft 14 a motor pinion 15 which is in engagement with a gear 16 which is held on a shaft 17 in a rotationally fixed manner. On the shaft 17 rotatably sits a drum 18 as part of a percussion mechanism 13, the fixed Mitnehmerbo lzen 19 engages with play in a transverse bore of a pivot pin 20, which in turn is supported in a fork-shaped end of a drive piston 21. The drive piston 21 is designed as a hollow piston and acts via an air cushion on a striker 22 movably mounted therein. The drive piston 21 of the striking mechanism 13, which is driven axially to and fro via the drum 18, drives the striker 22 via the air cushion, which strikes its impact energy, for example, via a delivers die not shown or directly onto a tool 24 inserted into a tool holder 23. The tool 24 consists, for example, of a drill. Other types of tools can also be accommodated in the tool holder 23.

The tool 24 can be driven in a rotary manner via a rotary sleeve 25 of the transmission 12, which is only indicated schematically. For this purpose, the rotary sleeve 25 carries a gear 26, which is non-rotatable thereon, which meshes with a pinion 27, which is non-rotatably or coupled to the shaft 17 via a special safety coupling. Such a safety clutch in one embodiment is e.g. described in DE-OS 28 20 128, to which reference can be made here.

A special clutch 28 is arranged in the drive train from the engine 11 to the tool 24, which is shown only schematically here. This clutch is arranged in the rotary drive drive train in front of the branch of the striking mechanism 13. It is namely in the exemplary embodiment shown between the gear part driven by the motor pinion 15 in the form of the gear wheel 16 and the shaft 17 on the one hand and the gear train driving the striking mechanism 13 on the other hand, to which the shaft 17 for example, rotatable drum 18 and the driven parts of the striking mechanism 13, which are explained at the beginning.

In another embodiment, not shown, the coupling 28 is instead behind the branch shown, where it is arranged in the pure percussion drive branch, e.g. between the shaft 17 on the one hand and the drum 18 on the other hand, so that when the clutch 28 is disengaged the drive of the drum 18 is interrupted and thus the striking mechanism 13 stands still, even if the rotary drive which is still driven and rotating shaft 17 above is not interrupted is, but is still effective.

The clutch 28 is automatically disengaged depending on a size with an interruption of the driving activity of at least the striking mechanism 13. In this case, the gearbox complex adjoining it in FIG stands still, then also the drive rotating the rotating sleeve 25 and the tool 24 also stands still. If the clutch 28 is instead arranged between the shaft 17 and the drum 18, only the striking mechanism 13 stands still when the clutch 28 is disengaged. The clutch 28 is designed here as a clutch. It consists in particular of a non-positive clutch, e.g. from a friction clutch. The clutch 28 is designed as a servo switching clutch, which, by means of the existing energy diverted from the drive motor 11, e.g. is controllable by means of electrical or electromechanical energy.

In another exemplary embodiment, the coupling 28 can possibly also be designed as a form-fitting coupling, for example as a claw coupling. Then the clutch 28 should the branch of the striking mechanism 13 and be arranged as shown in FIG. 1, so that when the clutch is disengaged, in addition to the striking mechanism 13, the rotary drive is also stopped. Furthermore, it is advisable to switch off and stop the drive motor 11 at the same time when the clutch 28 is disengaged, so that the clutch 28 can be re-engaged later when the clutch 28 is disengaged.

As is only indicated in the drawings in connection with the clutch 28 shown, it has at least one disengaged release spring 29 which is biased and locked in the engaged state and which disengages automatically when the clutch 28 is disengaged. When the clutch 28 is actuated, the release spring 29 can be tensioned and locked again. Thus, the force to separate the two halves of the clutch 28 from the release spring 29 is supplied.

The handheld power tool also contains a sensor 30, only indicated schematically, which is fixedly arranged in the interior of the housing 10. The sensor 30 is designed in particular as an electrical sensor. However, it can also be designed as a mechanical or electromechanical sensor instead. The sensor 30 is in operative connection with the clutch 28 and acts on the clutch 28 as soon as it responds. In the exemplary embodiment shown, the sensor 30 is designed as an idle sensor, which detects the size of a path position of the tool 24 or a translationally moving part of the striking mechanism 13 located on the idle distance (FIG. 3) and then acts on the clutch 28 for automatic disengagement. Furthermore, the idling sensor is able to automatically detect the leaving of this position in the direction of the striking position and then the clutch 28 for automatic re-engagement to act upon. In the embodiment shown, in which the clutch 28 is located in front of the branch of the striking mechanism 13 in the drive train, not only the striking mechanism 13 is stopped when the clutch 28 is disengaged, so that the tool 24 is in the front region, namely the idling region, of its translation path, but the rotary drive is also switched off at the same time, so that the tool 24 does not rotate about the rotary drive axis 31.

In the embodiment shown, the sensor 30 is e.g. designed as an electrical limit switch. Furthermore, a control device 34, e.g. a switching logic, with which the sensor 30 is connected, wherein the sensor 30 can activate the control device 34 when activated. The sensor 30 can e.g. be designed as an electromagnetic sensor which activates the control device 34 when said path position is reached. The control device 34 is in turn in operative connection with the clutch 28 for disengaging and reinserting it (FIGS. 2, 4). If the sensor 30 responds, the control device 34 is activated, which in turn controls the clutch 28 electrically or electromechanically, e.g. electromagnetic, disengages. As soon as the tool 24 or a translationally reciprocating part of the striking mechanism 13, which is monitored by the sensor 30, is shifted from the idle position in FIG. 3 to the right on the translation path into the region of a striking position, this is detected by the sensor 30 and in addition, the control device 34 is also activated, which now controls the clutch 28 in the sense of engaging again.

With the hand-held power tool designed in this way, it is possible for the sensor 30 as the variable to reach a position on the idle st rec ke of the tool 24 or a part of the striking mechanism 13 which is moved in translation is detected and when this position is reached the clutch 28 is automatically disengaged and when leaving this position the clutch 28 is automatically engaged again. This is illustrated with the aid of FIG. 3. The overall translation path of the tool 24, or for example of the reciprocatingly driven drive piston 21, during impact operation corresponds to a distance of considerable length, which can only be approximately 22 mm, for example. When the striking mechanism 13 is switched on, the tool 24 is in the striking mode in a striking position shifted to the right on this route in FIG. Due to the acting impacts, the tool 24 carries out an oscillating movement which is carried out over a distance of 1/3 of the total translation path. The sensor 30 is e.g. B. not placed in this area, but, seen in Figure 3 from right to left, at least in the second or better still in the third third and thus on an area that the tool 24 or a reciprocatingly driven part of the striking mechanism 13th only reached in idle position. The sensor 30 is placed on this idle path, for example, in such a way that it is passed by the tool 24 going into the idle position and in the idle position the end of the tool 24 is on the left and at a distance from the sensor 30, so that the sensor 30 uses this as a criterion for idle operation and the application of the clutch 28 to the disengagement. Then the sensor 30 could be placed, for example, in the middle third of the translation path of the tool 24 or even further to the right. It depends on the design of the sensor 30 where it is ultimately located. If the sensor 30 responds when the tool is, for example, in overlap with it, the sensor 30 is reliably placed at a suitable point on the idling path, for example in the last third, as shown in FIG. 3 with a solid line Lines is shown. If the sensor 30 responds when it has been overrun by the tool 24 and there is no overlap in the idle position, the sensor 30 can be arranged, for example, in the middle position, as indicated by the broken line in FIG. 3.

In all, the Kerngeda nke is that that the idling position of the tool 24 or a reciprocating part of the striking mechanism 13 is detected by the sensor 30 during impact operation and then the clutch 2 is controlled so that it disengages. As soon as the tool 24 or said part of the striking mechanism 13 is shifted from this idling position to the right into the striking position by movement in FIGS. 1, 3, this is also detected by the sensor 30 and the clutch 28 is acted upon to re-engage. For everything, it does not depend on any force to be exerted by the user of the handheld power tool in order to achieve the engagement of the clutch for the impact operation and the disengagement of the clutch automatically in the event of idling. Rather, a reliable and high-quality idle shutdown is created, which does not require any additional operating or engagement forces from the user. Special idling devices or catching devices or the like are therefore unnecessary in such hand-held power tools. Another advantage of Vo rte i l is that almost any short idle paths are possible that can be used.

In FIG. 2 and in particular 4 it is indicated how the sensor 30 acts indirectly on the clutch 28. If the sensor 30 responds when the idling position has been reached, the sensor 30 activates the control device 34, in particular switching logic, which in turn leads a control pulse in the sense of disengaging the clutch to an electro-mechanical, for example electrical, actuator, in particular disengaging actuator 35. who then at the Clutch 28 engages to disengage them. After this, the tool 24 has been moved from the idle position to the striking position, then the clutch 28 is also re-engaged by the sensor 30 via the control device 34, which then in turn leads to a control pulse, for example on an actuator in the form of an engagement actuator 35, which engages clutch 28 to engage it. Like the disengaging actuator 35, the engaging actuator 36 can also be actuated by the control device 34, for example electromechanically, in particular electromagnetically.

In the following. Description to Figures 5 to 10, the same parts have the same reference numerals as in the preceding description.

In Fig. 5, a hand tool is shown schematically, which here consists of a hammer drill. The hammer drill has a housing 10 in which an electric drive motor 11, which is designed as a universal motor, a gear 12 and a striking mechanism 13 are arranged. designed in accordance with DE-0S 28 20 128, to which express reference is made here, so that particular details of the transmission 12 and the striking mechanism 13 need not be explained.

The drive motor 11 carries on the motor shaft 14 a motor pinion 15 which is in engagement with a gear 16 which is held on a shaft 17 in a rotationally fixed manner. On the shaft 17 there is a drum 18 as part of the striking mechanism 13, the driver pins 19 of which are fixed thereon with play in a transverse bore of a pivot pin 20 engages, which in turn is supported in a fork-shaped end of a drive piston 21. The drive piston 21 is designed as a hollow piston and acts via an air cushion on a striker 22 movably mounted therein. The drive piston 21 of the striking mechanism 13, driven axially back and forth via the drum 18, drives the striker 22 via the air cushion, which directly applies its impact energy to the striker 22 delivers tool 24 inserted into a tool holder 23. The tool 24 consists, for example, of a drill. Other types of tools can also be accommodated in the tool holder 23.

The tool .24 can be driven in a rotary manner via a rotary sleeve 25 of the transmission 12 which is only indicated schematically. For this purpose, the rotary sleeve 25 carries a gear 26, which is non-rotatable thereon, which meshes with a pinion 27, which is non-rotatably or coupled to the shaft 17 via a special safety coupling. Such a safety clutch is also described in DE-OS 28 20 128, to which reference is made.

A special coupling 28 is arranged in the drive train from the drive motor 11 to the tool 14, which is shown only schematically here. This clutch 28 is arranged in the rotary drive drive train in front of the branch of the striking mechanism 13. It is namely between the gear part driven by the motor pinion 15 in the form of the gear 16 and the shaft 17, on the one hand, and the gear train driving the striking mechanism 13, on the other hand, in the form of the drum 18, which is rotationally fixed to the shaft 17, and the parts of the striking mechanism 13 driven thereby. as explained at the beginning. In another embodiment, not shown, the clutch 28 is located behind the branch shown in the pure rotary drive branch, for example on the shaft 17 or between the pinion 27 and its drive from the shaft 17.

The clutch 28 is automatically disengaged depending on an overload size with an interruption of the drive activity. In this case, the gearbox complex adjoining it in FIG. 5 to the left of the clutch 28 is not driven, so that in this case both the striking mechanism 13 stands still and the drive rotating the rotating sleeve 25 and the tool 24. The clutch 28 is designed as a clutch. This can e.g. be designed as a positive coupling, in this case e.g. as a claw coupling. Then it is advisable to also switch off and stop the drive motor 11 when disengaging this clutch 28, so that later when the clutch 28 is re-engaged in the manner described above

Re-indentation can take place at a standstill. Instead, the clutch 28 can, as shown, be designed as a non-positive clutch, e.g. as a friction clutch. The clutch 28 is designed as a Servαschalt clutch, which by means of the existing energy diverted from the drive motor 11, e.g. is controllable by means of electrical or electro-mechanical energy.

As indicated in FIGS. 5-10 in connection with the clutch 28 shown, it has at least one release spring 29 that is biased and locked in the engaged state and which automatically disengages the clutch 28 when the clutch 28 is released. When the clutch 28 is actuated, the release spring 29 can be tensioned and locked again. Thus, the force to separate the two halves of the clutch 28 from the release spring 29 is supplied.

The handheld power tool also has a sensor 130, only indicated schematically, which is fixedly connected to the housing 10 and is expediently located in the interior of the housing 10. The sensor 130 is designed as an electrical or mechanical or electromechanical sensor. The sensor 130 is operatively connected to the clutch 28 (Fig. 6-10) and acts on the clutch 28 when a movement size of the hand-held hand tool is exceeded. In the exemplary embodiment shown, the sensor 130 is designed as a rotation sensor which, as a movement variable, detects the path and / or the speed and / or the acceleration of an external pivoting movement of the hand-held hand-held power tool in space around a rotary drive axis 31 of the driven tool 24.

The hand-held power tool also has an engaging set 32 which can be reached from the outside of the machine, in particular manually operated, and which, for example, consists of an actuating button. If the clutch 28 has been disengaged, it can be re-engaged directly or indirectly and mechanically, electrically or electromagnetically by means of the engagement actuator 32. In the exemplary embodiment shown in FIGS. 8-10, the sensor 130 is designed as a mechanical inertia switch and mechanically coupled to the clutch 28 to disengage it via an indicated lever 33. The lever 33 bearing the sensor 30 at the end is freely pivotable in the housing 10 about a schematically indicated pivot axis 38, which runs approximately parallel to the central axis of the clutch 28, an approximately U-shaped claw at the end of the lever 33 being so dimensioned and is designed so that it can hold the clutch 28 in the engaged state according to FIGS. 9 and 10 in this engaged state. The claw is brought, for example, approximately radially from the outside to both compressed coupling halves, which are overlapped together by the claw so that the release spring 29 remains in the compressed state and the clutch 28 cannot disengage. In FIG. 10, the direction of rotation of the tool 24 is symbolized schematically by arrow 41. If the tool 24 is blocked in the rock, for example, the handheld power tool is thrown around in the direction of the arrow 40. The sensor 30 responds, which in this exemplary embodiment as a mechanical inertia switch, together with the lever 33 and the claw engaging on the clutch 28, is pivoted about the pivot axis 35 in the direction of the arrow 39 and so that the claw at the end of the lever 33 is the two coupling halves Clutch 28 releases, so that the compressed release spring 29 can automatically move the clutch 28 into the disengaged position shown in FIG.

FIG. 8 schematically shows an engagement actuator 32 which is mechanically coupled to the clutch 28 to engage it via an internal lever 37. If the clutch 28 is to be engaged again, starting from the disengaged position shown in FIG. 8, then the engagement actuator 32 is pressed, which is mechanically via the lever 37 pushes the left half in FIG. 8 by compressing the release spring 29 onto the right coupling half until the engaged position according to FIG. 9 is reached, in which the islaue at the end of the lever 33 then automatically engages over both compressed coupling halves of the clutch 28.

In the exemplary embodiment shown in FIGS. 6 and 7, there is additionally a control device 34 in the hand machine tool, e.g. a switching logic, with which both the sensor 130 and the engagement actuator 32 are connected, each of which can activate the control device when it becomes effective. In this case, sensor 130 is designed as an electromechanical sensor, which activates control device 34 in the event of an overload. The control device 34 is in turn in operative connection with the clutch 28 for disengaging and reinserting it (FIGS. 6, 7). If the sensor 130 responds, the control device 34 is activated, which in turn controls the clutch 28 electrically or electromechanically, e.g. electromagnetic, disengages. If the engagement actuator 32 is then actuated from the outside and there is no overload, the actuation of the engagement actuator 32 likewise activates the control device 34, which now controls the clutch 28 in the sense of re-engagement.

With the hand-held power tool which is designed, it is possible that a movement variable of the hand-held hand-held power tool in space is detected as an overload variable via the sensor 130 and the clutch 28 is automatically disengaged when a predetermined value of this movement variable is exceeded. In this case, the sensor 130 can be designed such that it detects, as a movement variable, a path that the handheld power tool traverses. One way, for example, is the swivel angle of a swiveling movement of the hand tool around Rotary drive axis 31 into consideration, the rotation sensor 30 then responding, for example, when a permissible pivoting movement of, for example, 10 ° pivoting angle, is triggered and causes the clutch 28 to disengage in the manner described. Instead of this or also additionally, the speed and / or acceleration with which the hand-held power tool moves in space can also be detected by means of the sensor 130 as the movement variable. The main idea here is to use the rotation of the housing 10 of the hand-held power tool when the driven tool 24 is blocked - in other words, it receives an angular momentum - as a signal for switching off the rotary drive when this movement quantity is exceeded by disengaging the clutch 28. Then the drive is interrupted, so that the rotary actuation of the tool 24 stops, while the drive part located in FIG. 5 on the right of the clutch 28, in particular the drive motor 11 with gear 15, 16, can continue to rotate freely. Only if the clutch 28 is designed as a positive clutch, it is advisable to disconnect and switch off the drive motor 11 from the mains at the same time as the clutch 28 is disengaged. For everything, it is irrelevant how firmly the user holds the handheld power tool and how stable he is. Irrespective of this, the εrlautεrtε overload device ensures that inadmissible twisting of the hand-held power tool and thus the hand of the user holding it with the risk of injuries associated with it are prevented. The safety guaranteed by means of the overload device is always pending, regardless of the working torque of the hand tool that the user applies with the holding torque. The user therefore does not need to have a holding torque that is far too large for most of the time in anticipation of a possible blocking. Rather, he can be relaxed and relaxed with work much less effort and concentrate better on the actual machining process. Thus, with the help of the overload device with simple, inexpensive means, protection of the person working with the hand tool against injuries by hurling the hand tool when the rotating tool 24 is blocked, in particular protection against hurling the hand tool, for example, when there is tool 24 in the workpiece , for example in stone, concrete or the like. The path and / or the speed and / or the acceleration of an external swiveling movement of the hand-held power tool about the rotary drive axis 31 is thus recorded as the movement variable. If this movement quantity exceeds a predetermined value, this will be the

Sensor 30 is detected, which then disengages clutch 28 directly (FIGS. 8-10 or indirectly (FIGS. 6, 7). In the case of direct actuation, clutch 28 is disengaged mechanically via lever 33. In indirect actuation, the sensor activates 130 when the predetermined value of the movement quantity diε control device 34, in particular switching logic, which in turn leads to a control pulse in the sense of disengaging the clutch on an electromechanical, for example electrical, actuator, in particular disengaging actuator 35, which then leads to clutch 28 on the clutch 28 If the specified value of the movement quantity which caused the clutch 28 to be disengaged has been fallen below, the clutch 28 is re-engaged, for example by manually pressing in the engagement adjuster 32, which is then directly or indirectly and mechanically, electrically or electromechanically causes the clutch 28 to be re-engaged 8-10, the clutch 28 is immediately and mechanically re-engaged by means of the engagement adjuster 32 6 and 7, on the other hand, the control device 34, in particular switching logic, is activated by, for example, manually pressing in the engagement actuator 32, which then in turn leads to a control pulse, for example on an actuator in the form of an engagement actuator 36, to the clutch 28 attacking their engagement. The engagement actuator 36 is actuated by the control device 34, for example electromechanically, in particular electromagnetically.

It is clear that the two embodiments of the basic idea of interrupting the drive activity of the hand-held machine tool, as shown and described in FIGS. 1 to 4 and 5 or 10, are also very advantageous on a single machine can be used. A synergy effect then results here, since the electronics processing the measured electrical signals are of course smaller than the sum of those of the two embodiments.

FIGS. 11 and 12 show two further exemplary embodiments of the invention. FIG. 11 shows a hammer drill in which the clutch 28 is arranged behind the striking mechanism. In addition, there is a holding device 50 in the drive train between coupling 28 and tool 24, via which the named drive train can be connected to the housing 10 of the rotary hammer. The holding device 50 is designed as a known, electrically triggerable brake.

If the clutch 28 is released in the manner described above, only the drive train for rotating the tool is interrupted. By the brake 50 actuated at the same time, the housing of the hammer drill is ultimately firmly connected to the tool 24. As a result, the angular momentum, which was given, for example, when the drilling tool 24 was blocked in the workpiece in the housing 10 and which led to the release of the clutch 28, can be caught. Injuries to the operator by the described angular momentum are thus reliably avoided.

In the exemplary embodiment of the invention described in FIG. 12, the clutch 28 and the holding device (brake 50) are already in the drive train between the motor 11 and the striking mechanism. In this exemplary embodiment, the striking mechanism is also stopped in addition to the rotary drive when the clutch 28 is triggered.

Claims

Expectations

1. A method for interrupting the drive activity, in particular at least the impact drive activity, of a handheld power tool in the drive train from its drive motor (11) to its driving and / or rotatingly driven tool (24), in which a clutch arranged in the drive train is automatically disengaged depending on a size and is engaged again, characterized in that the quantity of reaching a travel position on the idle path of a translationally moving striking mechanism part or tool (24) is recorded and when this travel position is reached the clutch (28) is automatically disengaged and when leaving this travel position the clutch ( 28) is automatically re-engaged.

2. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that the clutch (28) is automatically disengaged when reaching the position from the direction of the striking position.

3. The method according to claim 1 or 2, characterized in that the clutch (28) is automatically engaged when leaving the path position in the direction of the striking position.

4. The method according to any one of claims 1-3, d a d u r ch g e k e n e z e i c h n e t that one detects as the path position the front position of the translationally moving tool (24) during striking operation or this actuating striking mechanism part, in particular an air cushion striking mechanism, of the handheld power tool, which corresponds to the idle position.

5. The method according to any one of claims 1-4, characterized in that with a arranged in the hand tool, in particular electrical, mechanical or electromechanical, sensor (30) detects the travel position and the sensor (30) when reaching this travel position, the clutch (28 ) disengages directly or indirectly mechanically, electrically or electromechanically.

6. The method according to claim 5, so that the sensor (30) activates a control device (34), in particular a switching logic, when this path position is reached, which in turn activates a control pulse on an especially electromechanical, e.g. electromagnetic, actuator (35), in particular disengaging actuator, leads, which acts on the clutch (28) to disengage it.

7. The method according to any one of claims 1-6, that the clutch (28) is automatically engaged again after disengaging the clutch (28) and leaving the travel position in the direction of the striking position.

8. The method according to any one of claims 5-7, characterized in that the sensor (30), the control device (34), in particular switching logic, at Leaving the path position in the direction of the striking position is activated and the control device (34) in turn leads a control pulse to an in particular electromechanical, for example electromagnetic, actuator (36), in particular engagement actuator, which acts on the clutch (28) to engage it.

9. A method for interrupting the drive activity, in particular the rotary drive activity, of a hand tool in the drive train from its drive motor (11) to its tool (24), in which a clutch arranged in the drive train is automatically disengaged depending on a measured size, in particular according to one of the Claims 1 or 8, characterized in that a size of a movement size of the hand-held hand-held power tool in space is recorded and the clutch (28) is automatically disengaged when a predetermined value of this movement size is exceeded.

10. The method of claim 9, d a d u r c h g e k e n n z e i c h n e t that one detects as a movement quantity a path through which the hand tool machine travels.

11. Verfahrεn according to claim 9, d a d u r c h g e k e n e z e i c h n e t that one detects as a movement variable the speed at which the hand-held hand tool moves in space.

12. The method according to claim 9, characterized in that the acceleration with which the hand-held power tool moves in space is detected as the movement variable.

13. The method according to any one of claims 9-12, d a d u r c h g e k e n n z e i c h n e t that one detects the path and / or the speed and / or the acceleration as a movement variable.

14. The method according to any one of claims 9-13, d a d u r c h g e k e n n z e i c h n e t that one detects the path and / or the speed and / or the acceleration of an external pivoting movement of the hand tool about a rotary drive axis (31) of the driven tool (24) as the movement variable.

15. The method according to any one of claims 9-14, characterized in that with a fixed with the handheld machine tool, in particular electrical, mechanical or electromechanical, sensor (30), the movement size is detected and the sensor (30) when exceeding the predetermined value of the movement size Coupling (28) disengages directly or indirectly mechanically, electrically or electromechanically.

16. The method according to claim 15, so that the sensor (30) disengages the clutch (28) immediately and mechanically when the predetermined value of the movement quantity is exceeded.

17. The method according to claim 15, characterized in that the sensor (30) activates a control device (34), in particular a switching logic, when the predetermined value of the movement quantity is exceeded, which in turn activates a control pulse on an in particular electromechanical, for example electromagnetic, Actuator (35), in particular disengaging actuator, which engages the clutch (28) to disengage it.

18. The method according to one of claims 9 -17, characterized in that after disengaging the clutch (28) and falling below the predetermined value of the movement size, the clutch (28) as required, in particular by manual actuation of an engagement adjuster (32), directly or indirectly mechanically , electrically or electromagnetically.

19. The method according to claim 18, so that the clutch actuator (32) engages the clutch (28) directly and mechanically.

20. The method according to claim 18, so that the engaging element (32) activates the control device (34), in particular switching logic, when it is actuated, which in turn emits a control pulse to a particularly electromechanical, e.g. electromagnetic, actuator (36), in particular engagement actuator, leads, which acts on the clutch (28) to engage it.

21. Hand tool, in particular rotary hammer, in the drive train from the drive motor (11) to the driven one

Tool (24) a clutch is arranged, which is automatically disengaged depending on a measured size with an interruption of the drive activity, in particular impact or

Rotary drive activity, in particular for performing the method according to claim 1 or 9, characterized in that the coupling is designed as a positive or non-positive coupling (28) and that in particular an electrical, mechanical or electromechanical sensor (30) is arranged in the hand-held power tool, preferably permanently connected, which is in operative connection with the clutch (28) and acts upon it when the measured size is exceeded for automatic disengagement.

22. Hand machine tool according to claim 21, so that the sensor (30) is designed as an idle sensor which detects the idle position in impact operation.

23. Hand machine tool according to claim 21 or 22, so that the sensor (30) is designed as a limit switch.

24. Hand tool according to claim 22 or 23, characterized in that the sensor (30) is designed as an electromechanical sensor which is operatively connected to a control device (34), in particular switching logic, inside the hand tool and activates it when the path position is reached, and that the control device (34) is in operative connection with the clutch (28) for disengaging and reinserting it.

25. Hand tool according to one of claims 21 - 24, characterized in that the clutch (28) is designed as a servo clutch and can be actuated by means of electrical or electromechanical, branched from the drive motor (11) of the power tool.

26. Hand tool according to claim 24 or 25, g e k e n e z e i c h n e t d u r c h an electromechanical, in particular electromagnetic, actuator, in particular disengaging actuator (35) and / or engaging actuator (36), the clutch (28) which can be acted upon by the control device (34).

27. Hand tool according to one of claims 21 - 26, characterized in that the clutch (28) has at least one pretensioned and locked Ausrückεdεr (29) in the engaged state, which automatically disengages when the clutch (28) is disengaged and the engages when depressed the clutch (28) can be tensioned and locked again.

28. Hand tool according to one of claims 21 - 27, d a d u r c h g e k e n n z e i c h n e t that the clutch (28) in the Ξchlagwεrkantriebstranges or in particular in the rotary drive train is preferably arranged before its branch to the percussion drive, the hammer drill.

29. Hand tool according to claim 28, so that the clutch (28) is arranged in the drive train between the output-side gear (16, 17) driven by the motor pinion (15) on the one hand and the gear train driving the striking mechanism (13) on the other hand.

30. Hand tool according to claim 21, characterized in that the sensor (30) is designed as a rotation sensor, which as a movement large the path and / or the speed and / or the acceleration of an outer swing movement of the hand-held hand-held power tool in space around a rotary drive axis (31) of the driven tool (24).

31. Hand tool machine according to claim 30, so that the sensor (30) is designed as a mechanical inertia switch.

32. Hand tool according to claim 31, so that the mechanical inertia switch is coupled mechanically via a lever (33) to the clutch (28) to disengage it and works on it.

33. Hand tool according to claim 21 or 30, characterized in that the sensor (30) is designed as an electromechanical sensor which is in operative connection with a control device (34), in particular switching logic, inside the hand tool and activates it in the event of an overload, and that the Control device (34) is operatively connected to the clutch (28) for disengaging and reinserting it.

34. Hand tool according to claim 33, characterized in that the clutch (28) is designed as a servo clutch and by means of electrical or electromechanical, from Drive motor (11) of the branched-off power tool can be actuated.

35. Hand tool according to claim 34, g e k e n e z e i c h n e t d u r c h an electromechanical, in particular electromagnetic, actuator, in particular disengaging actuator (35) and / or engaging actuator (36), the clutch (28) which can be acted upon by the control device (34).

36. Hand tool according to one of claims 21 or 30 - 35, characterized d u r c h one of

The machine exterior can be reached, especially manually operated, by means of which the clutch (28) can be mechanically, electrically or electromechanically reinserted directly or indirectly.

37. Hand tool according to claim 36, so that the engagement actuator (32) is mechanically coupled to the clutch (28) for engaging and engaging with the clutch (28) for this engagement.

38. Hand tool according to claims 33 and 36, d a d u r c h g e k e n n z e i c h n e t that the engagement actuator (32) with the control device (34), in particular switching logic, is in communication and activates this when actuated.

39. Hand tool according to one of claims 21 or 30 - 38, characterized in that the clutch (28) has at least one disengaged and locked release spring (29) in the engaged state, diε disengages the clutch (28) and disengages them automatically with relaxation which can be tensioned and locked again when the clutch (28) is actuated.

40. Hand tool according to one of claims 21 or

30 - 39, because of that the

Switching clutch (28) is arranged in the rotary drive drive train, before or after its branch to the percussion drive, of the rotary hammer.

41. Hand tool according to claim 40, so that the clutch (28) is arranged in the drive train between the output-side gear (16, 17) driven by the motor pinion (15) on the one hand and the gear train driving the striking mechanism (13) on the other hand.

42. Hand tool according to one of claims 21 to 41, characterized in that the clutch is a wrap spring clutch which can be actuated electromagnetically when the size is exceeded

43. Hand tool according to one of the preceding claims, characterized in that the drive train between the coupling (28) and tool (24) by a holding device (50), in particular brake, can be connected to the housing (10) of the hand tool when the drive train for Motor (11) is interrupted by the clutch (28).

44. Hand tool according to claim 43, characterized in that the holding device (50) connects the drive train for rotating the tool (24) and / or the striking mechanism (13) with the housing of the hand tool.