GB2404891A

GB2404891A - Operating module for hand-held electric machine tool

Info

Publication number: GB2404891A
Application number: GB0417767A
Authority: GB
Inventors: Hans-Joachim Vogt; Dietmar Hahn; Andreas Heilmann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2003-08-18
Filing date: 2004-08-10
Publication date: 2005-02-16
Anticipated expiration: 2024-08-10
Also published as: GB0417767D0; CN100519092C; GB2404891B; CN1579712A; DE10337260A1; CH696902A5

Abstract

An electric hammer drill 10 has three modes of operation, rotational (drilling), torque controlled rotational (screwdriving) or percussion-rotation (hammer-drilling). An operating module 12 is provided on the drill which comprises a single switching means for selecting any one of the three operational modes. The module may also incorporate means for setting upper and/or lower limits on the rotation speed (drilling mode) or torque (screwdriving mode) and may include a switching means to activate a gear change mechanism (eg. to reverse direction of rotation of the drill shaft). The module may further incorporate display means to provide a visual indication of the operating status of the drill, including mode and any limits set. In one embodiment, sliding rocker switch 22, combines the mode selection and limit setting functions in a single control and in an alternative embodiment a dial is provided which enables mode changing and stepped control of the limits in a single control. Alternatively the operating mode may be changed by a first control and limits set by pairs of 'increase-decrease' buttons (not shown).

Description

240489 1

OPERATING MODULE FOR AN ELECTRIC MACHINE TOOL

The present invention relates to an operating module for an electric machine tool according to the pre-characterising part of claim 1.

With hand-held electric machine tools such as drills, percussion drills or hammer drills, it is known to provide a setting means, normally a setting dial, as well as an associated operating mode changeover switch for setting a maximum torque in screwing operations or a maximum rotational speed in drilling operations. The setting means and operating mode changeover switch are as a rule arranged on the handle and on the upper side of the appliance. In order to switch between drilling and percussion drilling, a gear-type changeover switch is normally additionally provided in order to permit, in addition to a rotation, also an axial movement of a drilling tool. Usually an electronics module, which is responsible for adjusting the torque and rotational speed, is combined with the setting dial and with the operating mode changeover switch in order to avoid complicated wiring in the electric machine tool. This measure already provides for a small minimum height of the electronics module, setting means and operating mode changeover switch, resulting from the combined height of the setting dial, the thickness of the associated potentiometer, and the prescribed electrical safety interspacings.

The invention is based on an operating module for an electric machine tool, in particular a hand-held electric machine tool, in which at least one changeover switch is provided for purposes of switching between operating modes.

It is proposed that a changeover switch for switching between torque operations and rotational speed operations as well as a changeover switch for switching between drilling operations and percussion drilling operations be combined in a common switching means. The handling of the electric machine tool is thereby simplified and greater configurational margins are possible as regards the layout and design of the electric machine tool. The user no longer has to execute a separate switching between torque operations and rotational speed operations.

If the switching means comprises at least three switching positions, the individual switching position may in each case be specifically associated with an operating state. The switching positions are non-reversible and an incorrect operation is avoided. The switching means may conveniently be designed as a rotary switch or as a slide switch. The operating module is insensitive to vibrations, impact/shock moisture and dust. The switching means can easily be operated with gloves, which simplifies the operation of the electric machine tool.

If at least one setting means is provided to adjust the limiting value of a rotational speed or a torque, a corresponding limiting value may be preselected for each operating mode. An undesirable exceeding of an upper torque or a maximum rotational speed can be avoided.

If the setting means is designed as a rocker switch, in which in one position a limiting value can be increased and in another position a limiting value can be reduced, then the setting means can be easily and reliably operated, also with gloves.

The limiting value may be a minimum value or a maximum value or some other pre- selected value. Other setting means, such as for example setting dials, that appear suitable to the person skilled in the art may however also be used. The setting means and the switching means may be formed from separate structural parts or from an individual structural part, with which switching and setting functions are associated, such as for example functions to adjust a limiting value of a rotational speed and/or a torque as well as functions for switching between a torque operation and a rotational speed operation and/or between a pure drilling operation and a percussion drilling operation.

If the setting means is subdivided into two switches, in which one switch is provided to increase a limiting value and the other switch to reduce a limiting value, the setting means may be flexibly arranged. The operation is clear. In all variants the setting means may be designed so that under continuous actuation a limiting value is continuously approached and with fast or multiple actuation, e.g. double clicking or engagement of the setting means, a limiting value is selected as quickly as possible. When the limiting value is reached the setting means can then be disengaged. Minimum values as well as maximum values or some other pre-selected value may be set. The setting means can be operated in a user-friendly manner.

If a drilling operation with rotational speed setting is associated with a first switching position of the switching means, then an available rotational speed range can be provided automatically, e.g. by an electronics unit, from an evaluation of the switching position. An actuation of the setting means then results in an increase or decrease of the rotational speed in the rotational speed range. A gear change to a percussion drilling operation is prevented since a co-operation of the switching means with a switching lever in this switching position is prevented by a suitable design of the switching lever.

If a screwing operation with torque setting is associated with a second switching position of the switching means, then likewise an available torque range can be provided from an evaluation of the switching position, and similarly a Redefined rotational speed range can automatically be allocated in order to maintain the torque under load. An actuation of the setting means then results in an increase or decrease of the torque in the torque range. An unintentional gear change is prevented since the switching lever is suitably designed and in this switching position no cooperation with the switching means is possible.

If a percussion drilling operation with rotational speed setting is associated with a third switching position of the switching means, then an available rotational speed range can be provided from an evaluation ofthe switching position.

Furthermore, a switching lever arrangement with which a gear change of a gear of the electric machine tool can be actuated is associated with the third switching position. An undesired engagement of the percussion drilling mode in the other switching positions for screwing or drilling is reliably avoided. Further switching arrangements, such as for example electromagnetic switching arrangements, etc., that appear convenient to the person skilled in the art are however also conceivable.

If optical display means on which information of an actual operating state of the electric machine tool can be displayed are associated with the operating module and/or with the setting means, this permits a reliable handling. The information is clearly arranged and easily legible to the user. Conveniently a display may be provided for a torque or a rotational speed or for a display of the operating time, a display giving information concerning necessary customer service, a fault display, for example overload, and/or an operating mode display.

If the setting means and/or the switching means and/or the optical display means are arranged in a common electronics module, then an ergonomic, space- saving construction is achieved. It is possible to use compact functional units and identical parts in the production.

If the electronics module is arranged on an upper side of the electric machine tool substantially directly over an electric drive motor of the electric machine tool, the electric machine tool can be constructed very flat, which simplifies handling and creates an advantageous, robust impression. The operating module is easily visible and accessible. Setting means and switching means can be implemented simply and symmetrically for right-handed and left-handed users. Prescribed electrical air gaps and leakage gaps can easily be maintained.

In order to avoid additional switching means and/or setting means and thus associated costs, switching means and/or setting means already present on the electric machine tool can advantageously be utilised, such as in particular a switching means associated with a gear change, etc. The invention is particularly suitable for hand-held electric machine tools, since in particular a manual operation of the electric machine tools is facilitated.

Further advantages are disclosed in the following drawings and description.

The drawings show two examples of implementation of the invention. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will conveniently also consider the features individually and devise useful further combinations.

In the drawings: Fig. 1 shows in profile a preferred electric machine tool; Fig. 2 is a plan view of the preferred electric machine tool with a first variant of switching means and setting means; Fig. 3 is a further variant of switching means and setting means, Fig. 4 shows diagrammatically a circuit arrangement for controlling the operating module; and Fig. 5 shows a further alternative switching means.

A preferred electric machine tool 10 is shown in profile in Fig. 1. The electric machine tool]0 comprises a conventional switch (trigger) 16 in a handle and a tool receiver (chuck) 18 for receiving an exchangeable tool 20. On the upper side 14 of the electric machine tool l 0 is arranged an operating module 12, by means of which a user can select an operating mode, for example screwing, drilling, percussion drilling, and for each operating mode can adjust a limiting value, either of a torque or of a rotational speed, uniquely associated with this operating mode. It can be seen that the surface of the electric machine tool 10 is designed to be substantially flat.

A plan view of the upper side 14 of the electric machine tool 10 of Fig. 1 is shown in Fig. 2. The operating module 12 comprises a switching means 22 in which setting means 24, 26 are integrated. The switching means 22 is preferably designed as a slide switch and can move backwards and forwards along an axis 38 of the appliance, as indicated by the double arrow. The axis 38 of the appliance lies in the viewing direction of the user when the latter actuates the electric machine tool 10 with a tool 20 inserted into the too] receiver 18, so that the operating module 12 also

lies in the field of view.

The switching means 22 preferably comprises three switching positions and, when the slide switch 22 is moved, switches between various operating modes, for example screwing in a first switching position, drilling in a second switching position and percussion drilling in a third switching position. The setting means 24, 26 is preferably designed as a double key and serves, when the plus key 24 is actuated, to increase a rotational speed or torque, or when the minus key 26 is actuated, to reduce a rotational speed or torque, depending on the selected operating mode. In this connection minimum values as well as maximum values or some other preselected value may be set. Whether an operating mode that is selected on the switching means 22 is associated with a rotational speed setting or with a torque setting is determined by means of an electronic circuit, which is discussed hereinafter with reference to Fig.4.

An optical main display means 28A arranged on the switching means 22 designed as a slide switch and a display means 28B complementing the function of the main display means 28A are both associated with the operating module 12 and/or with the setting means 24, 26, on which display means information can be shown regarding an actual operating state of the electric machine tool 10, for example the selected operating mode, a deviation from the selected maximum value or minimum value, a power reserve that is stir] available, etc., etc. The selected operating mode may alternatively be permanently readable or permanently displayable by means of permanently arranged images/icons on the respective switching position, or by display means in an electronic display of the display mear s 28A, 28B.

The display means 28A, 28B may in particular comprise light-emitting diodes, LED displays, LCD displays, organic displays or other optical means and may be designed for example as light-emitting diode panels, as a segment display or as a plastics display.

Fig. 3 shows an alternative embodiment of the operating module 12 according to the invention. The operating module 12 comprises a setting means 32 and a switching means 30 separated therefrom. The setting means 32 and switching means are arranged along the axis 38 of the appliance. The switching means 30 is preferably designed as a rotary switch or dial. The setting means 32 is designed as a rocker switch, wherein in one rocker position a limiting value of the torque or rotational speed can be increased, and in the other rocker position this limiting value can be reduced, independently of the selected operating mode. The operation of the operating mode 12 is also user-friendly and simple in this embodiment. The setting means 32 comprises an optical display means 34 in the form of a panel. A further optical display means 36 in addition to the switching means 30 is arranged along the axis of the appliance.

It is advantageous to arrange the operating module 12 in an electronics module on the upper side 14 of the electric machine tool 10 substantially directly over an electric drive motor 42 of the electric machine tool 10. In this way an electric machine too] ] O that is overall flat and very handy can be obtained.

A preferred circuit arrangement in Fig. 4 shows an electronics unit 40 connected to a supply voltage. The electronics unit 40 is a constituent part of the electronics module mentioned above. A pressure on the switch] 6 in the handle of the electric machine tool 10 (Fig. 1) actuates the switch 50 in order to release a flow of current to the electronics unit 40 and to the drive motor 42 of the electric machine tool 10. The switching means 22, 30 corresponds to a multiple switch 44 that has three switching positions 44a, 44b, 44c. The multiple switch 44 is triggered when the switching means 22, 30 is actuated.

A drilling operation with rotational speed setting is associated with a first switching position 44a of the switching means 22, 30, a screwing operation with torque setting is associated with a second switching position 44b, and a percussion drilling operation with rotational speed setting is associated with a third switching position 44c. A switching lever arrangement (not shown) is associated on the appliance with the third switching position 44c, by means of which a switching of a gear (not shown) of the electric machine tool 10 can be actuated. The provision of a switching lever arrangement is generally known for switching between drilling and percussion drilling. In the third switching position 44c the switching lever arrangement now performs the gear change to the percussion drilling operation.

The user selects via the switching means 22, 30 one of the switching positions 44a, 44b, 44c. The corresponding information is processed in the electronics unit 40 and the associated rotational speed setting or torque setting is assigned to the actual switching position 44a, 44b, 44c.

The switches 46, 48 are associated with the respective setting means 24, 26, 32 (Fig. 2, Fig. 3). This is actuated by the user and the information is in turn processed in the electronics unit 40 and a value or limiting value of the torque or rotational speed is selected.

The electronics unit 40 also includes a comfort function so that the type of actuation of the setting means 24, 26, 32 triggers a predetermined action. A specified presetting of the torque or rotational speed can be selected immediately by quickly depressing the key twice, by increased pressure or by locking engagement or the like.

Accordingly a further depression of the setting means 24, 26, 32 until the value is reached is no longer necessary. In the basic function a single depression of the key denotes an increase of a rotational speed stage or torque stage or a reduction, corresponding to the actuated key of the setting means 24, 26, 32. If the respective setting means 24, 26, 32 is held longer, then the set value continuously increases or decreases. A corresponding evaluation electronics circuit is provided in the electronics unit 40. Obviously other functions that seem sensible to the person skilled in the art may also be implemented. The person skilled in the art wild also employ other types of setting means 24, 26, 32, for example a rotary switch instead of a touch key or rocker switch, if this appears convenient.

Fig. 5 shows an alternative switching means 52 designed as a rotary switch, with which switching functions as well as setting functions are associated. The switching means 52 is subdivided into three circular segments 54, 56, 58, in which a first circular segment 54 is associated with a screwing operation, a second circular segment 56 is associated with a drilling operation and a third circular segment 58 is associated with a percussion drilling/chiselling operation. Six differentiated positions are provided in each case within the circular segments 54, 56, 58, which in the circular segment 54 allocated to screwing operations are associated with different maximum torques, in the circular segment 56 allocated to drilling operations are associated with different rotational speeds per unit time, and in the circular segment 58 allocated to percussion drilling or chiselling operations are associated with different numbers of impacts per unit time. A gear mechanism, more specifically for switching an impact tool and a rotary drive on and off, can be engaged via the switching means 52. In addition the switching means 52 is coupled to an electronics unit, in particular to a control unit, via which the rotational speeds per unit time, the number of impacts per unit time and the various maximum torques can be selected and via which in addition a switch can be made between a rotational speed operation and a torque operation. In order to save an additional switching means and thus associated costs, an already existing switching means of the electric machine tool is advantageously employed, such as in particular a switching means provided for a gear change, which as a rule is arranged laterally on the electric machine tool.

Claims

CLAIMS: 1. Operating module for an electric machine tool in particular a

hand- held electric machine tool (10), in which at least one changeover switch is provided for switching between operating modes, characterised in that a changeover switch for switching between torque operations and rotational speed operations as well as a changeover switch for switching between drilling operations and percussion drilling operations are combined in a joint switching means.
2. Operating module according to claim 1, characterised in that the switching means comprises at least three switching positions.
3. Operating module according to claim 1 or 2, characterised in that at least one setting means is provided for setting a limiting value of a rotational speed or a torque.
4. Operating module according to claim 3, characterised in that the setting means is designed as a rocker switch, wherein in one rocker position a limiting value can be increased and in another rocker position a limiting value can be reduced.
5. Operating module according to claim 3, characterised in that the setting means are subdivided into two switches, wherein one switch is provided for increasing a limiting value and the other switch (26) is provided for decreasing a limiting value.
6. Operating module according to one of the preceding claims, characterised in that a drilling operation with rotational speed setting is associated with a first switching position of the switching means.
7. Operating module according to one of the preceding claims, characterised in that a screwing operation with torque setting is associated with a second switching position of the switching means.
8. Operating module according to one of the preceding claims, characterized in that a percussion drilling operation with rotational speed setting is associated with a third switching position of the switching means.
9. Operating module according to claim 8, characterized in that a switching lever arrangement is associated with the third switching position, with which a gear change mechanism of a gear of the electric machine tool can be actuated.
10. Operating module according to one of the preceding claims, characterized in -that optical display means on which information concerning an actual operating state of the electric machine tool can be displayed are associated with the operating module and/or with the setting means.
11. Operating module according to one of the preceding claims, characterized in that the setting means and the switching means and/or the optical display means are arranged in a joint electronics module.
12. Operating module according to one of the preceding claims, characterized in that the operating module is arranged on an upper side of the electric machine tool substantially directly over an electric drive motor of the electric machine tool.
13. Operating module substantially as herein described with reference to the accompanying drawings.