EP0272209B1 - Hand tool - Google Patents

Abstract

The hand tool has a toolholder (1) which is equipped with different tools for different uses, the tools requiring specific operating modes of the hand tool for the most efficient possible work. For this, the tools have different contours of their insertion shank (41). A feeler device consisting of at least one control element (16) and a slide (12) senses the particular contour and initiates a corresponding switching operation for obtaining the appropriate operating mode. <IMAGE>

Description

The invention relates to a hand-held device with a tool holder for tools and a sensing device for detecting the contour of the tools for initiating a switching operation.

From DE-OS 29 43 508 an electrically operated hand-held device in the form of a drilling machine is known which carries out switching operations controlled by the contour of the tools used, the appropriate operating mode being set by the switching operations. The contour of the tools is mechanically determined by means of a feeler device designed as a displaceable pin, which leads to different displacement movements of the feeler device. In accordance with the displacement path, an electrical controller is set by the touch device, which in turn switches the drive of the hand-held device to a respectively correct value.

The contour of the tools used for the control process is formed by the end face of a threaded sleeve facing in the direction of insertion of the tools. The threaded sleeve is screwed to an adapter in which a drill is stuck. The tools, consisting of a threaded sleeve, adapter and drill, are exchangeably held in the tool holder of the hand-held device by a quick-release fastener. To set the appropriate operating mode, the threaded sleeve is brought into a corresponding axial position in relation to the adapter before the tools are inserted into the tool holder.

This tool-related control is not suitable for hand-held devices, such as rotary hammers, which impart axially directed impact impulses to the tools, since the action of the tools causes them to intermittently move axially. This axial movement of the tools would be transferred to the feeler device and would make a control process impossible.

DE-A-2 106 023 relates to a tool or tool holder for machines with an automatic tool changing device. At the end of the tool holder or tool shank, a number of grooves and / or webs running in the longitudinal direction of the shank are provided and a feeler element is arranged in the region of each groove or web. Depending on the type of tool, the various webs can be partially flattened, so that coding is created. These webs are scanned by means of contact tongues of microswitches which are arranged in a star shape around the tool holder shaft. A switch is assigned to each bar. Depending on which or which microswitch is pressed, the type of tool can be determined automatically.

The invention has for its object to provide a hand-held device with a probe suitable for tool-related initiation of switching operations, even when impact pulses are delivered to the tools.

According to the invention, the object is achieved in that the feeler device has a slide which can be adjusted along the tool axis and at least one control element which can be inserted essentially transversely to the tool axis into the guide bore of the tool holder, the slide is axially supported on the control element disengaged from the guide bore and at in the guide bore engages the control element over which the axial displacement of the slide serves to initiate the switching process.

By dividing the feeler device into a slide and at least one control element, which can be inserted into the guide bore of the tool holder essentially transversely to the tool axis and thus also transversely to the direction of displacement of the slide, radial contours of the tools can be scanned and used to initiate a switching operation. The radial contour to be scanned can extend over an axial path along the tools. Axial movement of the tools to the extent of this distance therefore does not influence the tactile position of the control element. As a result, this feeler is also suitable when the tools are given impact impulses.

If a tool is inserted into the tool holder, the contour of which allows the control element to be inserted into the guide bore, the displacement limit for the slide is eliminated, so that the slide transfers the control element. The resulting displacement path of the slide is used to initiate a switching process, for example to switch to a different gear stage or to change the impact power. However, if a tool is inserted into the tool holder, the contour of which holds the control element in the disengaged position, the displacement path of the slide falls away. A switching process in the aforementioned sense can not be triggered in the device, so the tool for example, the standard functions of the device intended for such cases are conveyed.

To achieve several switching options, several control elements are preferably provided, which can be inserted one after the other into the guide bore of the tool holder. Depending on the number of control elements, the tools can have the same number of longitudinal grooves or fewer longitudinal grooves or no longitudinal groove at all, depending on the most favorable operating mode.

For the sake of simplicity, the control elements are designed as balls and are mounted in radial through openings of the tool holder. The diameter of the balls is selected so that it exceeds the wall thickness of the essentially sleeve-shaped tool holder. As a result, the balls forcibly project beyond the tool holder radially outward or protrude into the guide bore of the tool holder.

According to a preferred embodiment, the control elements are arranged offset to one another in the circumferential direction of the tool holder. By means of an axially stepped end face of the slide which serves to run up on a disengaged locking element, depending on the radial position of the locking elements, different axial positions of the slide can be achieved to initiate a switching operation. Each control element is assigned a different axial step on the end face of the slide.

According to a further embodiment of the invention, the control elements are arranged offset to one another in the axial direction of the tool holder. This arrangement of the control elements allows an axially unstaged and thus simple design of the end face of the slide. Depending on the radial position of the control elements, the slide can thus shift into the respective axial position in order to initiate the corresponding switching operation. The axially offset arrangement of the Control elements can also be combined with the arrangement of control elements offset in the circumferential direction, such a combination allowing further switching positions.

The slide is advantageously designed as a sleeve comprising the tool holder. The circumferential face of the sleeve facing the tool is supported on the disengaged control element.

Preferably, the slide is acted upon by a spring element driving it against the control elements. Depending on the radial position of the control elements, the spring element, preferably a compression spring, automatically drives the sleeve into the respective axial switching position. If all the control elements are engaged, the sleeve passes over the control elements and assumes the switching position corresponding to the maximum displacement path. The sleeve is returned to the starting position by overcoming the spring force, for example by manually moving the sleeve from the outside. The locking operation of the tools is expediently coupled with this displacement operation.

According to a preferred embodiment, the push button initiates the switching process mechanically, optically or electrically. The shifting of the slide of the push button device is used as a signal for the switching process.

To mechanically initiate the switching process, the pushbutton device expediently has a shifting link for a multi-stage transmission. The shift gate can be arranged in one piece on the slide or, for example, be part of a separate shift rod that interacts with the slide. The shifting gate is designed, for example, as a pull wedge, which optionally couples different drive wheels for the transmission of rotary motion to the tool holder.

According to a further embodiment, the pushbutton device has an induction core, which interacts with a sensor, for the electrical initiation of the switching process inductive switching signals. The induction core is expediently arranged in one piece on the slide and lies at least in an axial position of the slide in the induction area of the sensor. To achieve a plurality of switching operations, the induction core advantageously has sections of different volumes arranged one behind the other along the direction of displacement. The sections of different volumes can be stepped or continuously spaced differently from the sensor.

Depending on the axial position of the slide, the sensor emits different electrical switching signals through the action of the induction core, which preferably indirectly effect the respective switching process. The switching process can be, for example, a change in the speed or the direction of rotation.

According to a further embodiment of the invention, the contour to be scanned by the control element can be achieved in that the insertion shaft has at least one recess for the control element of the pushbutton device, such a recess being designed, for example, as a longitudinal groove. When the tool is inserted, this longitudinal groove lies in the range of movement of the control element, so that it can be immersed in the longitudinal groove. As a result, the displacement limit for the slide falls away, so that the slide can move, this displacement path being used as a switching operation in the device.

If, on the other hand, a tool that is not provided with a recess, for example in the form of the aforementioned longitudinal groove, is inserted into the tool holder, the control element cannot move into the guide bore and thus forms a displacement limitation for the slide. As a result, the slide remains in a different axial position, which can be used to initiate a switching process in this position as well, but which leads to other operating points.

Advantageously, the recess, for example in the form of a longitudinal groove, has an axial extension of the control element that is immersed several times, so as not to hinder in particular the axial movement of the tools, for example in the event of impact transmission.

A plurality of depressions are preferably arranged along the circumference of the insertion shaft. The division of these depressions, which in turn are formed as longitudinal grooves, can be uniform or non-uniform. In cooperation with a slide, which has, for example, an axially stepped end face facing the locking elements, different axial positions can be achieved for initiating switching operations.

A further possibility of arranging the depressions expediently consists in that several depressions are arranged axially offset from one another. This axial offset can be seen in connection with the distribution along the circumference of the insertion end, so that a large number of coding possibilities result in combination. The axial displacement is to be understood in particular in such a way that the beginning and end of adjacent depressions, for example in the form of longitudinal grooves, are at axially different locations, which can be achieved above all by different lengths of the depressions.

Fig. 1

den Vorderbereich eines Handgerätes mit Tastvorrichtung zur mechanischen Einleitung eines Schaltvorganges und eingesetztem Werkzeug im Längsschnitt;

Fig. 2

den Vorderbereich des Handgerätes nach Fig. 1 mit eingesetztem, ein Paar Längsnuten zum Abtasten durch die Tastvorrichtung aufweisendem Werkzeug;

Fig. 3

den Vorderbereich des Handgerätes nach Fig. 1 mit eingesetztem, zwei Paare Längsnuten zum Abtasten durch die Tastvorrichtung aufweisendem Werkzeug;

Fig. 4

einen Schnitt durch den Vorderbereich des Handgerätes nach Fig. 1 bis 3, gemäss Schnittverlauf IV-IV in Fig. 3;

Fig. 5

den Vorderbereich einer anderen Ausführungsform eines Handgerätes mit Tastvorrichtung zur elektrischen Einleitung eines Schaltvorganges und eingesetztem Werkzeug im Längsschnitt;

Fig. 6

den Vorderbereich des Handgerätes nach Fig. 5 mit eingesetztem, ein Paar Längsnuten zum Abtasten durch die Tastvorrichtung aufweisendem Werkzeug;

Fig. 7

den Vorderbereich des Handgerätes nach Fig. 5 mit eingesetztem, zwei Paare Längsnuten zum Abtasten durch die Tastvorrichtung aufweisendem Werkzeug.

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

Fig. 1

the front area of a hand-held device with a pushbutton for mechanical initiation of a switching process and the tool used in longitudinal section;

Fig. 2

the front area of the handheld device according to Figure 1 with inserted, a pair of longitudinal grooves for scanning by the probe having tool.

Fig. 3

the front area of the handheld device according to Figure 1 with inserted, two pairs of longitudinal grooves for scanning by the probe having tool.

Fig. 4

a section through the front region of the handheld device according to Figures 1 to 3, according to the section IV-IV in Fig. 3.

Fig. 5

the front area of another embodiment of a hand-held device with a pushbutton device for the electrical initiation of a switching process and the tool used in longitudinal section;

Fig. 6

the front area of the hand-held device according to FIG. 5 with inserted, a pair of longitudinal grooves for scanning by the probe having tool;

Fig. 7

5 with inserted, two pairs of longitudinal grooves for scanning by the tool having the probe device.

The handheld devices shown with the front area in FIGS. 1 to 7 are rotary hammers which are able to convey clamped tools rotational movement and impacts. The impact energy given off to the tools is passed on to a workpiece, for which purpose a limited axial displacement of the tools in the hand tools is required.

1 to 4 has an essentially sleeve-shaped tool holder 1, to which a guide cylinder 2 is connected in one piece with the same axis.

The guide cylinder 2 is penetrated by a bearing bore 3 into which a guide bore 4 of smaller diameter protruding through the tool holder 1 opens. A striker 5 is displaceable in the bearing bore 3 and is arranged in a sealing manner by a ring 6. The striker 5, which is moved in a reciprocating motion by a drive (not shown), is used for the continuous loading of a tool, for example a drill, which projects with its insert shaft 7 into the guide bore 4 of the tool holder 1.

For limitedly displaceable mounting and rotary driving of the tool, the insert shaft 7 has two diametrically opposed driving grooves 8 into which locking rollers 9 on the device side engage. Furthermore, the insertion shaft 7 of the tool used in FIG. 1 has a cylindrical outer surface. The locking rollers 9 are mounted in window-like openings 11 of the tool holder 1 and are held in the locking position shown by a sleeve-shaped slide 12 which concentrically surrounds the tool holder 1.

To unlock the locking rollers 9, the slide 12 in the illustration according to FIGS. 1 to 3 can be shifted to the right and then rotated, as a result of which known recesses on the inside of the slide 12 release the locking rollers 9 radially outwards. The slide 12 is moved by manual attack from the outside, for which purpose an actuating collar 13 is firmly connected to the slide 12. The force of a compression spring 14, which is supported on the one hand on the inside of the actuating sleeve 13 and on the other hand on a shoulder of the guide cylinder 2, must be overcome.

In the end section of the tool holder 1 pointing in the drilling direction, two through openings 15, 15ʹ are provided at an axial distance from one another, which are offset from one another in the circumferential direction by 90 °, as shown in FIG. In the passage openings 15, 15ʹ is in each case a control element 16, 16ʹ mounted in the form of a ball. The control elements 16, 16ʹ are supported on the cylindrical outer surface of the insert shaft 7 of the tool according to FIG. 1 and thus project radially beyond the outer contour of the tool holder 1. The slide 12 can thus be moved from the compression spring 14 only up to the control element 16 closer to the locking rollers 9 in FIG. 1 to the left. The left end face of the slide 12 which has run up on the control element 16 is shown in broken lines in FIG. 1 to illustrate this control position.

The axial displacements of the slide 12 are also carried out by a switching rod 17 which is held in contact with the right end face of the slide 12 by a further compression spring 18. The shift rod 17 is mounted in the wall of the guide cylinder 2 and surrounded by a sealing ring 19. The end of the shift rod 17 facing away from the slide 12 is designed as a shifting link 21 in the form of a drawing wedge. The shifting gate 21 is mounted in a radially open groove 22 of the guide cylinder 2 and is thus supported in the circumferential direction of the guide cylinder 2.

On the guide cylinder 2 there are three gears 23, 24, 25 of different sizes, each of which has a spline profile. Depending on the axial position of the slide 12, the shift link 21 of the shift rod 17, which communicates with the slide 12, engages with a groove 26, 27, 28 of the spline profiles of the gears 23, 24, 25. FIG. 1 shows the engagement of the shift link 21 in the Groove 26, whereby the gear 23 is rotationally coupled to the guide cylinder 1.

With the gears 23, 24, 25 mesh spur gears 31, 32, 33, which are non-rotatably seated on a drive shaft 34. As a result of the coupling connection of the gear 23 to the guide cylinder 2, the rotational movement of the spur gear 31 is transmitted to the guide cylinder 2, which corresponds to the smallest switchable speed of the guide cylinder 2. The Drive shaft 34 is rotatably supported in a device housing 35, for which purpose bearings 36, 37 are used. A roller bearing 38 and a sealing ring 39 serve to pivot or seal the guide cylinder 2 in the device housing 35.

The insertion shaft 41 of another tool shown in FIG. 2 has a pair of longitudinal grooves 42 arranged diametrically to one another in the section adjoining the driving grooves 43 counter to the insertion direction for automatic adjustment of the rotational speed suitable for this tool, in this illustration only the front longitudinal groove 42 is recognizable. The control element 16, which is axially closer to the locking rollers 9, can be immersed in the concealed longitudinal groove 42 of the inserted insertion shaft 41. This is caused by the slide 12 acted upon by the compression spring 14, which thus moves this control element 16 and is supported on the axially closest control element 16 'which projects radially beyond the tool holder 1. The shifting gate 21 of the communicating shift rod 17 thus enters the groove 27 of the central gear 24, so that a higher speed is imparted to the guide cylinder 2 compared to the position in FIG. 1.

In FIG. 3, the shank 45 of another tool has two pairs of longitudinal grooves 46, 47, which are offset axially and by 90 ° to one another, for immersing both control elements 16, 16ʹ, as FIG. 4 illustrates. The longitudinal grooves 46, 47 are in turn arranged in the region of the insertion shaft 45 which is adjacent to the driving grooves 48 counter to the insertion direction. The slider 12 can run over the immersed control elements 16, 16ʹ and runs to limit movement on a pot-shaped stop part 49 which is firmly connected to the tool holder 1. In the axial position achieved by the sliding of the slide 12 on the stop part 49, the shifting link 21 couples the gearwheel 25 to the guide cylinder 2, which corresponds to the greatest switchable speed.

The diametrical arrangement in pairs of the longitudinal grooves 42, 46, 47 allows the insertion or locking of the insertion shaft 41, 45 in both alternative locking rotational positions while achieving control.

To change the tool, as described above, the slide 12 is moved by manual engagement on the actuating sleeve 13 in the insertion direction of the tool shaft 7, 41, 45. As a result, the control elements 16, 16ʹ are released radially outwards and, after inserting a respective tool and releasing the slide 12 again, assume one of the switching-effective positions shown in FIGS. 1 to 4.

The hand-held device shown in FIGS. 5 to 7 is also a hammer drill, the construction of which and the design of the tools largely correspond to FIGS. 1 to 4. For reasons of simplification, the constructively and functionally analog device parts are therefore provided with the same reference numerals and a new explanation of these parts is omitted.

The slide 12 has an induction core 51 in the end region directed in the direction of insertion of the tools. The induction core 51 is subdivided into axial sections of different volumes, the sections also having different radial distances from an inductive sensor 52 of a type known per se. The sensor 52 is held in an insulation ring 53, which is fixed on the device housing 35. Depending on the axial switching position of the slide 12, which is dependent on the contour of the insertion shaft 7, 41, 45 of the respective tool, the induction core 51 with the section of large volume and small radial distance (FIG. 5) or the section of small volume is located above sensor 52 large radial distance (FIG. 6) or the sensor 52 is not covered by the induction core 51 at all (FIG. 7). Depending on the coverage situation of the sensor 52 by the induction core 51, the magnetic conductivity changes for the magnetic field built up by the sensor, which leads to different usable switching signals in the sensor 52. These switching signals are used to carry out corresponding switching operations. For example, the speed or the direction of rotation of the drive motor can be controlled. Instead of an inductive sensor 52, however, an optical sensor can also be used, for example.

Claims (13)

1. Hand tool comprising a tool holder (1) for tools and a sensing device for determing the contour of the tools for initiation of a switching process, characterised in that the sensing device comprises a slide (12), which is adjustable along the tools, and at least one control element (16, 16'), which is insertable into the guide bore (4) of the tool holder (1), substantially transversely to the tool axis, in that the slide (12) axially supports itself against the control element (16, 16') which is pushed out of the guide bore (4) by the tool, and moves over it when the control element (16, 16') is pushed into the guide bore (4), whereby the axial displacement of the slide (12) serves to initiate the switching process.
2. Hand tool according to claim 1, characterised in that several control elements (16, 16') are provided which are insertable one after the other into the guide bore (4) of the tool holder.
3. Hand tool according to claim 1 or 2, characterised in that the control elements (16, 16') are formed as balls and mounted in radial passages (15, 15') of the tool holder.
4. Hand tool according to one of claims 1 to 3, characterised in that the control elements (16, 16') are arranged transposed to one another in the circumferential direction of the tool holder (1).
5. Hand tool according to one of claims 1 to 4, characterised in that the control elements (16, 16') are arranged transposed to one another in the axial direction of the tool holder (1).
6. Hand tool according to one of claims 1 to 5, characterised in that the slide (12) is formed as a sleeve which embraces the tool holder (1).
7. Hand tool according to one of claims 1 to 6, characterised in that the slide (12) is loaded by a spring element (14) which forces it towards the control elements (16, 16').
8. Hand tool, in particular according to one of claims 1 to 7, characterised in that the sensing device mechanically, optically or electrically initiates the switching process.
9. Hand tool according to claim 8, characterised in that the sensing device has a switch gate (21) for a multi-stage gearing for the mechanical initiation of the switching process.
10. Hand tool according to claim 8, characterised in that the sensing device has an induction core (51) which co-acts with a sensor (52) for producing inductive switch signals to electrically initiate the switching process.
11. Hand tool according to one of claims 1 to 10 with a tool, whereby the mounting shaft of the tool (41, 45) has at least one recess (42, 46) for the control element (16) of the sensing device.
12. Hand tool according to claim 11, with several recesses (42, 46; 47) arranged along the circumference of the mounting shaft (41, 45) of the tool.
13. Hand tool according to claim 11 or 12, with several recesses (42, 46; 47) arranged axially transposed relative to each other.

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