GB2432036A

GB2432036A - Power Tool

Info

Publication number: GB2432036A
Application number: GB0621762A
Authority: GB
Inventors: Peter Jordan; Jochen Krauter
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2005-11-03
Filing date: 2006-11-01
Publication date: 2007-05-09
Anticipated expiration: 2026-11-01
Also published as: CN1958242B; JP5221866B2; CN1958242A; DE102005052428A1; GB2432036B; GB0621762D0; JP2007125691A; DE102005052428B4; ITMI20062095A1

Abstract

The invention starts from a power tool comprising a battery (10) arranged in a receiving housing (11) and a drive (13), arranged in a housing (12), of an insertion tool driven via a gearing (14) so as to rotate and/or be percussive, and comprising a handle (15) connected to the housing (12). It is proposed that at least the receiving housing (11) of the battery (10) is connected to the housing (12) by a vibration damping element (16).

Description

* 2432036 Power tool

Prior art

The invention starts from a power tool according to the pre-characterising clause of claim 1.

To allow cable-free working it is known to operate hand-held power tools via a battery or what is known as a power pack. The batteries or power packs are conventionally fastened to the power tool by a latching connection.

Electrical contacting of the battery is achieved via a contact holder. The contact holder is conventionally resiliently mounted to dampen vibrations during operation of the power tool. In the case of cordless hammer drills in particular the striking mechanism leads to severe vibration of the device, so resilient mounting of the contact holder alone is not enough to adequately decouple the vibrations.

Unpleasant vibrations still occur, in particular in the region of the handle, owing to the vibration behaviour of the respective tool. Vibrations of this type lead to the operator tiring more quickly and to a reduction in the holding forces. In particular with operation over a long period, such as in the case of grinding tools, an operator is subject to an increased health risk. Vibrations can also lead to adverse effects on contacting of the battery in the case of battery-operated power tools. To prevent contacts from arcing the contacts according to the prior art have a special coating. The problem with this is that over time the coating is rubbed away by the vibrations and loses its effect.

Advantages of the invention With the battery-operated power tool according to the invention comprising a battery arranged in a receiving housing and a drive, arranged in a housing, at least the receiving housing of the battery is connected to the housing by a vibration damping element. Vibrations are advantageously reduced in the process and overall vibration of the device is reduced by a more advantageous mass distribution between a striking mechanism on the one hand and a damped mass on the other, with the damped mass being formed at least from the battery, handle, optionally electronic devices and/or a drive. It may be provided that only the battery is decoupled from the remainder of the mass in order to protect the battery in particular from vibrations. In a preferred variation it may also be provided that battery and handle together may be decoupled from the remaining mass. This makes an advantageous need-dependent adjustment possible. By decoupling battery and handle, the vibrations acting on the hand, arm, and shoulder regions of the user can be reduced. Overall the power tool according to the invention beneficially increases convenience of operation because the user, when holding the device at the battery and at the handle, is protected from vibrations. In addition the technical expenditure to configure the battery and the battery cells so as to be vibration-resistant can expediently be reduced.

A beneficial rigidity in guidance of the device as a whole is also achieved.

In an advantageous development the vibration damping element is arranged in such a way that a first mass fraction can be completely, or at least partially, decoupled from a second mass fraction, with the battery being associated with one of the two mass fractions.

Variations with respect to the elements associated with the mass fractions can advantageously be achieved to give a need-dependent adjustment. In this connection, in a first variation the battery can form the first mass fraction and at least the drive and the gearing as well as the handle the second mass fraction. In a further variation the handle may opLionally also be integrated in the first mass fraction, whereby battery and handle are decoupled as a unit from the second mass fraction. This achieves a particularly beneficial mass distribution. By combining the vibration damping element for battery and handle significant cost savings may be made. The vibration damping element can particularly preferably be constructed in one piece.

The mass fractions are preferably arranged in such a way that vibration damping is assisted. As a result the battery and all components, such as a contact holder contacting the battery, are protected against vibrations. The contact holder for contacting the battery can in particular be integrated in the receiving housing.

The risk of contact arcing, which according to the prior art may be triggered if the coating is rubbed away, is advantageously reduced by the vibration-protected contact holder-The vibration damping according to the invention of the battery and its components, in particular the battery cells and cell connections, as well as the contact holder, can advantageously be configured more simply and more cost efficiently. The invention is also associated with a reduction in time and costs in the case of the new development of battery and contact holder. Overall, numerous preliminary experiments, which were previously necessary, to ensure hammer capability of battery and contact holder can consequently be avoided.

One of the two mass fractions can be adjusted so as to be significantly larger than the other. In a preferred embodiment the first mass fraction can be adjusted so as to be selected as high as possible. In particular, the first mass fraction can be increased by device-specific elements that can be integrated. For example the first mass fraction can be increased by providing a charging device and components thereof in the handle, or by electronic devices for controlling even devices without a commutator. In devices with a commutator the commutator may also be protected from vibrations, and this has positive effects on rotational speed behaviour and an advantageous carbon! commutator service life can be achieved. As an alternative it may also be provided that the second mass fraction is adjusted so as to be as high as possible, for example by integrating device-specific elements that can be integrated, whereby a high mass is achieved and need-dependent, variation possibilities are provided.

The vibration damping element can be formed from a rubber element. Other materials or known spring damping elements, such as a spring suspension, and constructional damping elements are also conceivable which lead to damping of the vibrations. An active damping element may also be provided as the vibration damping element. Combinations of the individual damping elements within a device are also possible.

An unlatching device, for example an unlatching button for the battery, may optionally be damped and/or decoupled by the vibration damping element, if the unlatching device is arranged at the device-side. In this case the unlatching device can beneficially be integrated in damping.

It may also be provided that the unlatching device is integrated in the receiving housing of the battery.

Overall the power tool according to the invention achieves simple, efficient and inexpensive vibration damping which is particularly suitable for hammer drills with batteries or battery charging devices or complicated electronic devices in conjunction with EC motors.

Drawings Further embodiments, aspects and advantages of the invention also result, independently of their synopsis in the claims and without restricting the generality, from the embodiments of the invention illustrated hereinafter with reference to the drawings, in which: Fig. 1 shows a preferred embodiment of a battery-operated power tool according to the invention; Fig. 2 shows an alternative embodiment with a particularly preferred mass distribution of the individual elements, and Fig. 3 shows a further alternative embodiment.

Description of the embodiments

Identical elements are provided with the same numbers in each case in the figures.

Fig. 1 schematically shows a battery-operated power tool. A housing 12 is divided into a housing part 12a and a housing part 12b, with a drive 13 being arranged in housing part 12a and a gearing 14 being arranged in housing part 12b. An insertion tool (not shown) is driven so as to rotate or be percussive by the gearing 14. All components of the drive 13 and gearing 14 are arranged in a known manner and are not shown for the sake of simplicity. The mode of operation thereof is known to a person skilled in the art, so they will not be discussed in more detail here.

To receive the battery 10 there is provided a receiving housing 11. A contact holder 20 is formed for electrically contacting the battery 10. A handle 15 is connected to housing part 12a. According to the invention the receiving housing 11 of the battery 10 is connected to the housing 12 by a vibration damping element 16. The vibration damping element 16 is formed as a rubber element which leads to damping of the battery 10. At the device side there is provided an unlatching device 19 for the battery 10, with the unlatching device 19 being damped and/or decoupled by the vibration damping element 16 and thus being integrated in damping.

Fig. 2 shows an alternative embodiment of the power tool according to the invention in the form of a cordless hammer drill with a striking mechanism 21. At least one drive 13 and a gearing 14 are arranged in a housing 12. The drive 13 and the gearing 14 are components of a first mass fraction 17. A handle 15 is connected to the housing 12. A battery 10 is arranged in a receiving housing 10 connected to the housing 12. A contact holder 20 is again provided for contacting the battery 10. At the device side there is formed an unlatching device 19 for the battery 10, which device is integrated in the receiving housing 11 for the battery 10. The battery 10 and the handle 15 are components of a second mass fraction 18.

The handle 15 and the receiving housing 11 are connected to the housing 12 by a vibration damping element 16. The vibration damping element 16 is in particular arranged in such a way that the first mass fraction 17 can be decoupled from the second mass fraction 18. The mass fractions 17, 18 are arranged in such a way that vibration damping is assisted. As a result of the more favourable mass distribution thus produced, preferred vibration damping can be achieved, whereby the user, when holding the hammer drill at the battery 10 and at the handle 15, is largely protected from vibrations.

The first mass fraction 17 is in the process adjusted so as to be selected as high as possible and can be increased by integration of further device-specific elements that can be integrated, such as a charging device (not shown) or the like.

The vibration damping element 16 is formed in one piece from a rubber element which leads to damping of the battery 10, of the handle 15 and the remaining electronic components. Other components arranged at the device side, such as the unlatching device 19, are also protected from vibrations.

Fig. 3 shows a further alternative embodiment of a battery-operated power tool according to the invention, of which the construction substantially corresponds to that in Fig. 2. To avoid repetitions reference is therefore made to the above statements. In contrast to Fig. 2 the battery 10 and the handle IS in Fig. 3 are formed as an overall component, for example also as a one-piece component. As a result there is no decoupling between the battery 10 and the handle 15 but the battery 10 and handle 15 can be decoupled as a unit from the remaining components. A further variation possibility is therefore provided to achieve a need-dependent adjustment.

Claims

Claims 1. Power tool comprising a battery (10) arranged in a receiving

housing (11) and a drive (13), arranged in a housing (12), of an insertion tool driven via a gearing (14) so as to rotate and/or be percussive, and comprising a handle (15) connected to the housing (12), characterised in that at least the receiving housing (11) of the battery (10) is connected to the housing (12) by a vibration damping element (16)
2. Power tool according to claim 1, characterised in that the vibration damping element (16) is arranged in such a way that a first mass fraction (17) can be decoupled from a second mass fraction (18), with the battery (10) being associated with one of the two mass fractions (17, 18)
3. Power tool according to claim 2, characterised in that the handle (15) , as a component of the first mass fraction (17), can be decoupled from the second mass fraction.

4. Power tool according to claim 2, characterised in that the handle (15), as a component of the second mass fraction (18), can be decoupled from the first mass fraction (17) 5. Power tool according to any one of the preceding claims, characterised in that the mass fractions (17, 18) are arranged in such a way that vibration damping is assisted.

6. Power tool according to any one of the preceding claims 2 to 5, characterised in that the first mass fraction (17) is adjusted so as to be selected as high as possible.

7. Power tool according to any one of the preceding claims 2 to 5, characterised in that the second mass fraction (18) is adjusted so as to be selected as high as possible.

8. Power tool according to any one of the preceding claims 2 to 4, characterised in that the first mass fraction (17) or the second (mass fraction (18) and/or the battery (10) is increased by device-specific elements that can be integrated.

9. Power tool according to any one of the preceding claims, characterised in that the vibration damping element (16) is constructed in one piece.

10. Power tool according to any one of the preceding claims, characterised in that the vibration damping element (16) is formed from a rubber element.

11. Power tool according to any one of the preceding claims, characterised in that the vibration damping element (16) is formed from a spring element.

12. Power tool according to any one of the preceding claims, characterised in that an active damping element is provided as the vibration damping element (16) 1].

13. Power tool according to any one of the preceding claims, characterised in that an unlatching device (19) for the battery (10) is provided at the device-side.

14. Power tool according to claim 10, characterised in that the unlatching device (19) is damped and/or decoupled by the vibrating damping element (16) 15. Power tool according to claim JO or 11, characterised in that the unlatching device (19) is integrated in the receiving housing (11) of the battery (10) 16. A power tool substantially as herein described with reference to the accompanying drawings.