hand-held power tool, in particular drilling or screwdriving tools

Abstract

A hand-held power tool, in particular a drilling or screwdriving tool such as a cordless screwdriver, with a tool holder (8) slidably mounted in a housing, which can be driven by a drive unit (3) which can be switched on or off by an axial adjustment movement of the tool holder (8), characterized in that at least one lighting device (16) on the hand-held power tool (1) can be switched on and / or off by the adjustment movement of the tool holder (8), and the drive unit (3) can be switched on and / or off by a microswitch (10) actuated by the adjustment movement of the tool holder (8), which simultaneously switches the lighting device (16) on and off, wherein the microswitch (10) can be switched by an actuating element (9) which is axially fixed to the tool holder (8), wherein the actuating element (9) is arranged at least partially radially between the tool holder (8) and the lighting device (16).

Description

[0001] The invention relates to a hand-held power tool, in particular drilling or screwdriving devices such as a cordless screwdriver, according to the preamble of claim 1 or 4. State of the art

[0002] US Patent 5,557,990 describes a cordless screwdriver comprising a tool holder slidably mounted within a housing for holding a tool, the tool holder being driven by an electric drive motor. The cordless screwdriver is equipped with a push-start mechanism that enables automatic starting of the drive motor as soon as the tool is placed in the tool holder with pressure against the screw to be tightened or loosened and the tool holder is axially retracted a short distance into the housing, thereby actuating a switching mechanism that activates the electric motor. This involves axially displacing a radially projecting actuating element from the tool holder and pressing it against a microswitch, which controls the switching of the electric motor. A spring element returns the tool holder to its original position as soon as the screwdriver is removed from the screw.The actuating element, which is actuated by the tool holder and switches the microswitch on and off, is located in the housing of the machine tool on the axial end face of the tool holder and is pressed against the end face of the tool holder by the spring element.

[0003] Furthermore, a cordless screwdriver is known from DE 10 2004 051 913 A1, the tool holder of which is axially fixed within the housing and is driven by the rotor shaft of an electric drive motor. A switch for turning the drive motor on and off is located on the housing of the cordless screwdriver, and this switch can assume various positions in which different circuits of various electrical consumers are switched on or off. A work light is activated via one of these circuits, whereby, depending on the switch position, the work light can be activated either alone or together with the motor rotation.

[0004] DE 600 21 965 T2 describes a power tool with a light that can illuminate a work area and with a switch that allows a user to control a motor. The switch is coupled to the motor and can also be coupled to the light.

[0005] From US patent 2004 / 0156190A1, a battery-powered impact wrench is known, wherein the impact wrench has a light unit at a front end of the main housing and the light unit extends on a bottom of the gearbox housing. Disclosure of the invention

[0006] Starting from this state of the art, the invention is based on the objective of keeping the power consumption generated by a lighting device on a hand-held power tool low.

[0007] This problem is solved according to the invention by the features of claim 1 and 4. The dependent claims specify advantageous further developments.

[0008] The hand-held power tool according to the invention has a tool holder slidably mounted in a housing, which can be driven by a drive unit that can be switched on or off by an axial adjustment movement of the tool holder. This so-called push-start mechanism enables the drive unit of the hand-held power tool to be switched on or off automatically as soon as sufficient pressure is exerted on the tool holder in the axial direction, in particular when the tool held in the tool holder is placed on a screw or the like. When the pressure is removed, the tool holder can return to its axial starting position, whereupon the drive unit is automatically switched off.

[0009] According to the invention, a lighting device on the hand-held power tool can be switched on and / or off via the adjustment movement of the tool holder. The adjustment movement of the tool holder is thus used not only to switch the drive unit on and off, but also to switch the lighting device. This creates a functional link, at least during the switching-on movement, between actuating the drive unit and actuating the lighting device. Advantageously, the adjustment movement of the tool holder used to switch off the drive unit is also used to switch off the lighting device. Alternative switching mechanisms for switching off the lighting device are also possible, for example, switching off via a timer after a preset period following the switching off of the drive unit.

[0010] The lighting unit is advantageously switched on and off via a microswitch, which is activated by an actuating element that is axially fixed to the tool holder and thus performs the same axial adjustment movement as the tool holder. The microswitch preferably has the primary function of switching the drive unit on and off and is also used to switch the lighting element. In this way, a separate microswitch for the lighting element is unnecessary.

[0011] According to a further embodiment of the invention, the lighting device can be switched on and / or off via a rotation direction selector switch, which sets the left or right rotation of the tool holder. Actuation of the rotation direction selector switch is used in particular to switch on the lighting device; optionally, the lighting device can also be switched off via the rotation direction selector switch. Furthermore, it is possible to switch off the lighting device using a timer after a preset period has elapsed following the completion of the work process.If necessary, the lighting device is switched on and / or off using the on / off switch of the drive unit, whereby switching on and / or off via a separate switch is also possible in principle; in this version, the work area can be illuminated even before the screwdriver is placed on the screw, thus minimizing the risk of slipping off the screw.

[0012] Further advantages and practical designs can be found in the additional requirements, the figure description, and the drawings. These show: Fig. 1 a section through a hand-held power tool designed as a mains-powered straight screwdriver, equipped with a push-start mechanism, Fig. 2. The hand-held power tool in a view from below, Fig. 3 the hand-held power tool in side view, Fig. 4 one Fig. 1. Corresponding sectional view of the hand-held machine tool, but in an enlarged view of the front part in which the tool holder with the push-start mechanism is located. Fig. Figure 5 shows the output shaft of the hand-held machine tool in a single sectional view, which is connected at one end to a coupling element and at the other end has a recess for a spring element acting on the face of the tool holder.

[0013] In the figures, identical components are labelled with the same reference symbols.

[0014] How Fig. 1 and the enlarged representation according to Fig. As can be seen from Figure 4, the screwdriver 1 has a housing 2 in which an electric drive motor 3 is mounted. The rotor shaft 4 of the electric drive motor 3 is the drive shaft, which is connected via a planet carrier 5 from the gearbox to a coupling element 6. This coupling element is mounted on an output shaft 7 to transmit a preset maximum torque. The output shaft 7 is connected in a rotationally fixed manner to a tool holder 8 for receiving a tool, in particular a screwdriver or screwdriver bit. The tool holder 8 has a recess 11 on its end face in a section located outside the housing 2 for receiving the tool.

[0015] The tool holder 8 is held axially displaceable relative to the output shaft 7, but is positively connected to the output shaft in the direction of rotation, so that the rotational movement of the output shaft 7 is also transmitted to the tool holder 8. A recess 12 is provided in the end face of the output shaft 7 ( Fig. 4) is inserted, in which a spring element 13 designed as a compression spring is inserted. The spring element 13 is acted upon by a pin of tapered cross-section of the tool holder 8, which projects into the recess 12. Provided that no forces act on the tip of the tool holder 8 which receives the tool, the tool holder 8 is pushed out of the housing 2 of the cordless screwdriver 1 to its maximum extent in the axial direction due to the spring force of the spring element 13.

[0016] Due to the axial displacement of the tool holder 8, it can be moved axially inwards against the force of the spring element 13 as soon as the tool held in the recess 11 of the tool holder 8 is pressed against a screw or the like. Thereupon, the actuating element 9, which is fixedly arranged on the outer surface of the tool holder 8, comes into contact with the microswitch 10 and sets it to the on state, whereupon the microswitch 10, which is connected to the electronics of the drive motor 3, switches it on.The actuating element 9 consists of an actuating ring 14, which surrounds the cylindrical surface of the tool holder 8 and is advantageously held axially by two retaining rings, and an actuating tab 15, which is formed integrally with the actuating ring 14 and is designed as a radially projecting section that extends in the direction of the microswitch 10 and is designed to actuate the microswitch.

[0017] As soon as the tool held in the tool holder 8 is free of force, the tool holder 8 is axially moved back to its initial position by the action of the spring element 13, in which the tool holder protrudes maximally from the housing 1. The actuating element 9 then engages with the microswitch 10, so that the microswitch 10 changes from the on to the off state and the electric drive motor 3 is switched off.

[0018] The actuating element 9 is rigidly connected to the tool holder 8 in the axial direction, however, the actuating element 9 does not perform the rotary movement of the tool holder 8, but rather is rigidly connected to the housing 2 of the screwdriver 1 in the direction of rotation.

[0019] In the lower, front part of the housing 2 is a lighting element 16, which is in particular a light-emitting diode (LED) and illuminates the working area of ​​the hand-held power tool. For this purpose, the lighting element 16 is arranged at an oblique angle to the longitudinal axis 17 of the hand-held power tool, such that the free end face of the tool holder 8 and the areas in front of the end face are illuminated. The lighting element 16 is received in a recess 18 of the housing 2.

[0020] The lighting device 16 is switched on and off by the axial adjustment movement of the tool holder 8. This is achieved in particular by controlling the switching state of the lighting device 16 via the microswitch 10, which thus not only switches the electric drive motor 3 on and off, but also the lighting device 16 on and off. The switching on and off of the lighting device 16 is therefore carried out in the same way as the switching on and off of the electric drive motor. However, if necessary, only the switching on is carried out via the microswitch and thus via the electronics 27 of the drive motor, whereas the switching off is time-controlled via the electronics.

[0021] The switching on, and if necessary also the switching off, of the lighting device 16 can also be done via a direction-of-rotation setting switch 19 ( Fig. 2) by means of which the direction of rotation of the tool holder 8 can be set or switched. In the exemplary embodiment, the direction-of-rotation setting switch 19 is located in the side of the housing and is designed as a spring-loaded push button that presses on a further microswitch 28, which is located inside the screwdriver. The switching off of the lighting is usually time-controlled by the electronics 27 of the drive motor.

[0022] As further explained in Fig. 4 and Fig. As shown in Figure 5, the electric drive motor can also be switched off via a torque cut-off device. The torque cut-off device comprises a switching element 23, which is acted upon by a compression spring 24 and held in contact with a cut-off microswitch 25 by the compression spring. In the contact position of the switching element 23, the cut-off microswitch 25 is switched on. The switching element 23 is axially adjustable within the housing 2 and can be moved into the out-of-contact position with the cut-off microswitch 25 by a bearing disk 21, which is mounted on the outer surface of the output shaft 7 and is axially displaceable on the output shaft. The bearing disk 21 is located on the side of the output shaft facing the coupling element 6 and delimits a compression spring 20 designed as a coil spring, which is enclosed at the other end by a second bearing disk 22 on the output shaft 7.The bearing disc 21 moves axially away from the coupling member 6, provided that the tightening torque of the tool holder 8 or of the tool held therein corresponds to the torque of the coupling member 6. During this axial movement – ​​in the . Fig. 4 and Fig. 5 to the left - the switching element 23 is moved from the contact position with the cut-off microswitch 25 against the force of the compression spring 24 into the off-contact position, whereupon the cut-off microswitch 25 switches off the electric drive motor 3 via the electronics. As already explained, the cut-off can also be time-controlled via the electronics 27.

[0023] As soon as the bearing disc 21 is moved back into its initial position by the force of the compression spring 20, in which the bearing disc 21 rests axially against a ring shoulder 26 of the output shaft 7, the switching element 23 also moves back towards the cut-off microswitch 25 by the force of the compression spring 24, whereupon the latter is moved into the on position that switches on the electric drive motor.

[0024] Advantageously, the lighting device 16 is automatically switched off as soon as the switching-off microswitch 25 switches off the electric drive motor 3.

[0025] Furthermore, it may be advantageous to switch off the lighting device 16 via a timer after the work process has ended, i.e., after the electric drive motor has been switched off, only after a preset period of time has elapsed. In this case, the lighting device 16 is switched off only with a time delay after the electric drive motor has been switched off.

Claims

[1] Hand-held power tool, in particular a drilling or screwdriving tool such as a cordless screwdriver, with a tool holder (8) slidably mounted in a housing, which can be driven by a drive unit (3) which can be switched on or off when the tool holder (8) is moved axially, characterized by , that at least one lighting device (16) on the hand-held power tool (1) can be switched on and / or off via the adjustment movement of the tool holder (8), and that the drive unit (3) can be switched on and / or off via a microswitch (10) that can be actuated by the adjustment movement of the tool holder (8) and that simultaneously switches the lighting device (16) on and off, wherein the microswitch (10) can be switched via an actuating element (9) that is axially fixed to the tool holder (8), wherein the actuating element (9) is arranged at least partially radially between the tool holder (8) and the lighting device (16). [2] Hand-held power tool according to claim 1, characterized by that the microswitch (10) is arranged at least partially radially between the tool holder (8) and the lighting device (16). [3] Hand-held power tool according to claim 1 or 2, characterized by , that the lighting means (16) is received in a recess (18) of the housing (2). [4] Hand-held power tool, in particular a drilling or screwdriving tool such as a cordless screwdriver, in particular according to one of claims 1 to 3, with a tool holder (8) slidably mounted in a housing, which can be driven by a drive unit (3) which can be switched on or off during an axial adjustment movement of the tool holder (8), characterized by, that a lighting device (16) on the hand-held power tool (1) can be switched on and / or off via a direction-of-rotation setting switch (19) via which the direction of rotation of the tool holder (8) can be adjusted, wherein the lighting device (16) is received in a recess (18) of the housing (2). [5] Hand-held power tool according to any one of claims 1 to 4, characterized by , that the lighting means (16) is designed as an LED (Light Emitting Diode). [6] Hand-held power tool according to any one of claims 1 to 5, characterized by , that the lighting device (16) illuminates the working area of ​​the hand-held power tool (1). [7] Hand-held power tool according to any one of claims 1 to 6, characterized by , that the lighting device (16) is to be switched off via a timer after completion of the work process. [8] Hand-held power tool according to any one of claims 1 to 7, characterized by, that the lighting device (16) can be switched on and / or off via the on / off switch of the drive unit (3). [9] Hand-held power tool according to any one of claims 1 to 8, characterized by , that the drive unit (3) is an electric drive motor. [10] Hand-held power tool according to claim 6, characterized by , that the lighting means (16) is arranged at such an oblique angle to a longitudinal axis (17) of the hand-held power tool, in particular of the housing (2), that a free end face of the tool holder (8) and an area in front of the end face is illuminated. [11] Hand-held power tool according to any one of claims 1 to 10, characterized by , that the housing (2) is rod-shaped.

Images