Patent Description:
Cordless electrically operated power tools such as hedge trimmers, clearing saws, chain saws, brush cutters, trimmers, blowers, screw drivers, drills, hammer drills, nailers, staplers, polishing or grinding tools, need to be operated by batteries and provide a wide operating range since no electrical cables are provided.

Due to the increasing demand for elongated operating intervals for cordless power tools, larger batteries with higher capacities may be used. However, larger batteries having higher weights adversely affect comfort and ergonomy of operating the cordless tool, in particular power tool.

<CIT> discloses a hand-held tool supplied with power from a portable power system. The portable power system includes a battery pack, a power cord, a connector connecting the cord with the battery pack, a converter unit at the other end of the cord from the battery pack, and an adapter which fits on the converter unit and which inserts into a battery cavity of the normally battery-powered hand tool.

Therefore, in particular it is one object of the invention to provide a possibility of operating cordless tools, in particular cordless power tools, in a comfortable and/or ergonomic way even if energy sources, in particular battery systems, with larger loading or charging capacities are used. Further, an energy source assembly, power tool assembly and energy source and power tool assembly shall be provided.

This object is achieved by the subject-matter of claim <NUM>. Advantageous and preferred embodiments in particular result from the dependent claims.

A cordless power tool in particular shall be understood as a power tool, which, for ordinary operation, does not require a cable connection to a fixed or stationary electrical power source such as an energy generator or an electrical network or grid.

Rather, cordless power tools, in particular cordless power tools as rendered possible by the present invention, shall in particular be understood as power tools that can be operated in a stand-alone manner, in particular providing electric self-supply, such as for example with a passive energy source, such as a secondary battery or accumulator.

Note that a cordless power tool as rendered possible by the present invention, and in the broader sense, shall be understood as a stand-alone power tool or stand-alone power tool arrangement comprising battery packs either attached directly or indirectly thereto. Indirect connections may in particular comprise electrical connections to backpack battery packs and the like. It shall be stressed, that even in the event that the power tool is connected to a portable backpack energy source or the like via a cable, a respective power tool nevertheless is considered a cordless power tool. This in particular is the case as providing a backpack energy source does not require a fixed energy source or grid.

In embodiments, the power adapter comprises at least one balancing weight.

The balancing weight is adapted and configured for weight balancing the power tool in the indirect powering operation.

In other words, the balancing weight may be provided for acting as a counter weight for other operational components of the power tool in cases where no secondary battery of considerable weight is connected thereto. In particular, the counter weight may be configured so as to imitate the presence, in particular weight, of a conventional secondary battery, which hitherto is usual for cordless electrical power tools.

In particular, the counter weight may be adapted to provide the impression and to provide handling features comparable to the direct powering operation in which a secondary battery is provided and coupled to a respective interface of the power tool for powering the same. The balancing weight may provide advantageous weight distribution, and a favorable center of mass for the power tool. Also, in some cases the balancing weight may be provided for the reason to fulfill legal standards.

The proposed power adapter, either with or without balancing weight, may be used, for example, to connect to any type of cordless tool adapted to be powered by a network-independent energy source, i.e. off the line or by a battery energy source, such as a secondary battery, in particular a battery unit having enhanced loading capacity. The battery unit is a backpack energy source, i.e. a mobile energy source, in particular battery pack, specially adapted to be carried on the back of the user via at least one shoulder strap. Backpack energy sources are advantageous with respect to and can be designed for high wear comfort and ergonomics. However, also other types of energy sources, in particular battery packs, such as single shoulder strap type mobile battery packs, are conceivable.

Advantageously the power adapter comprises a housing adapted to accommodate, in particular on an outer and/or inner side, the balancing weight in the indirect powering operation. Furthermore, the power adapter may comprise a fixture unit into or onto which the balancing weight is fixed.

In an embodiment the fixture unit comprises a first fixture sub-unit and a second fixture sub-unit which are or can be connected by means of fastening elements to form the fixing unit. At least one balancing weight is now fixed to the first fixture sub-unit and/or the to the second fixture sub-unit before connection with the other sub-unit, preferably into a receiving space enclosed by a side wall of the sub-unit and/or is arranged in an inner space between the first fixture sub-unit and the second fixture sub-unit.

The housing is adapted to removably, in particular slidably, accommodate therein and/or thereon the fixture unit with the balancing weight.

In embodiments, the housing may comprise a base section and a cap or dome shaped cover. The base section and cover may be adapted to be combined and/or connected with each other to establish a casing, in particular an essentially closed housing, for accommodating therein in particular the balancing weight and other components of the power adapter.

In more general terms, the casing may provide an inner space for accommodating therein electronics, cables, in particular the balancing weight and/or other elements of the power adapter.

It is preferred, that the balancing weight is mounted to the base. Here, in general any type of mounting connections may be used, in particular clamping, screwing, snapping and the like.

Using the base section as a mounting base for the balancing weight may provide advantages for mounting the overall power adapter. In particular, the base section may be used and adapted for mounting or preassembling all the essential components of the adapter, and thereafter, the base section may be coupled to the cover to finally enclose all essential elements preassembled to the base.

In further embodiments, the base section comprises a recess adapted to accommodate a printed circuit board or similar control electronics, in particular for adequately controlling operation of the power adapter and power tool.

The power adapter may further comprise a support plate adapted to support the balancing weight while at the same time bridging the recess. The support plate is adequate for avoiding or preventing the balancing weight to exert mechanical loads to the control electronics, in particular printed circuit board.

The support plate is preferably adapted to bridge the recess in that flanges or webs are supported laterally adjacent to the recess, in particular on or at respective ribs. The flanges or webs may be implemented with or at the support plate or with or at the base section.

It shall be noted, that the control electronics, preferably a printed circuit board, which preferably is arranged below the balancing weight, optionally separated therefrom by the support plate, may be potted within the base section.

In embodiments, the power adapter may comprise a retaining bracket adapted and configured for bracket or clamp fastening the balancing weight to or against the base section.

Using a mounting or fastening bracket may be advantageous in view of assembly efficiency. The bracket may be U-shaped and/or pot-shaped and may in particular provide a rectangular clamping volume for clamping rectangular balancing weights.

It shall be noted that the clamping volume may be of any other shape. The balancing weight, by the way, may be any object or body suitable for being attached to the base section, in particular any metallic object of standardized shape having sufficient or adequate shape and corrosion resistance and other relevant characteristics.

In embodiments, the bracket comprises support sections or jibs, preferably protruding from the retaining bracket, preferably in a lateral direction. The support sections may be adapted to support the support bracket and balancing weight against at least one inner wall of the housing, in particular cover.

The support sections are advantageous for adequately fixing and supporting the balancing weight within the housing, in particular for protecting fastening elements and fixings against high impact loads.

The support sections may in addition be used and configured as cable support bars, which in particular shall mean that the support bars may be used for cable routing functions within the housing.

In further embodiments, the retaining bracket may comprise an integrated cable clamp section configured to clamp an electric supply cable of the power adapter, i.e. to be used for cable routing within the housing. Here, a high level of integration can be obtained, which may provide advantages during assembly. Further, as the bracket is adapted for retaining the balancing weight and therefore is comparatively robust, cables, such as supply cables, can be safely fixed.

In embodiments, the base section comprises a cable bushing. A cable bushing in particular shall mean a type of opening allowing a cable, in particular an electric supply cable, to be guided through the base section to the inner of the housing.

At the outer side, i.e. at the side external to the housing interior, the bushing may be implemented as a cone or funnel shaped deepening. Such a cone or funnel shaped deepening may comprise bended walls, in particular convex walls, adapted to allow smooth bending of the cable within the bushing, whilst avoiding sharp bends of the cable.

The cone or funnel, i.e. deepening, may be of rotational symmetric, i.e. isotropic, design. However, the cone or funnel may also be implemented in an anisotropic design, in which walls of the cone or funnel show different bending radii and ascent angles with respect to different bending directions.

In a view from the outside of the housing, the deepening comprises widening walls, which in particular shall mean that the axial cross section of the deepening gradually widens or increases towards the outside of the housing.

In an embodiment the power adapter comprises in or for a direct powering operation, instead of the at least one balancing weight, at least one battery for powering the power tool, wherein the weight of the battery is used for balancing the power tool. The power adapter in these cases may be adapted to the power tool, and the power tool then implements a self-powered device.

In particular, the power adapter is adapted to accommodate balancing weights of different mass in the indirect powering operation, which different masses are preferably adapted to different battery masses in the direct powering operation. The balancing weight in particular may be from steel and/or aluminum, and in particular any standard sized element or product suitable to be accommodated and/or arranged and/or fixed to the power adapter, in particular an inner interface of the power adapter, preferably housing.

In a further embodiment the power adapter comprises a slewable cable outlet for an electrical cable. The cable in particular may be used for connecting the power adapter to and with the energy source, in particular mobile energy source, in particular battery pack. Providing slewable cable outlets and/or connections adapted to connect cables to the power adapter in a slewable manner, greatly improves freedom of operation of the power tool, in particular as manual rotations or movements of the power tool can be balanced by a slewable cable outlet provided at the housing. In particular in operation, one advantage is that the cable may always be brought best operational position, or position to work.

In a preferred further embodiment the power adapter further comprises a display unit adapted to display a charging condition and/or other parameter such as temperature of the energy source at least in the electrically connected state. Note, that if the power connector itself comprises an additional battery, the display unit may also be used to display the charging state of the additional battery or battery unit. Displaying the charging state of the energy source at the power tool, in particular power adapter is advantageous, as such display is easily accessible and/or visible to a user operating with the power tool. In particular, if the energy source is a backpack energy source, checking the charging or loading state of the backpack energy source does not require removing the backpack energy source from the back.

Therefore, it is possible, that the power adapter itself may comprise batteries, such as conventional battery packs to be attached to the power tool. These batteries may in particular be used as intermediate storage means, charged by an external mobile energy source, such as a backpack energy battery pack.

However, it is also conceivable, and it is preferred that the power adapter does not contain any batteries or accumulators. In this case, the function of the power adapter is reduced to a simple connector without any charging functions.

The housing of the power adapter is preferably designed such that it complies with the design and dimensions of a respective conventional battery pack, in particular rechargeable battery pack, of the power tool. Here, the user of the power tool will not be confronted and will not have to customize to different designs. As in one configuration, such a housing may not contain any battery units, such a power adapter may also be called a "dummy battery".

The power adapter may have the same outside geometry and interfaces as conventional batteries used with the power tools. Note that using the proposed power tool does in general not require any mechanical and/or electrical adaptations of respective power tools. Conventional battery packs and the proposed power connector preferably are fully compatible.

The balance weight thus can be used and preferably is adapted such that an optimal center of gravity is obtained with the power tool.

The fixture unit may be adapted to comprise recesses or receiving spaces enclosed by side walls for accommodating therein one or more balance weight bodies. In particular the fixture unit may be adapted to clip or plug a balance weight body thereto.

In a further embodiment, the housing and/or fixture unit is/are adapted to accommodate one or several, i.e. at least one, balancing weight of the same or of different weight. If single balance weights are used, the power adapter will correspondingly have respective different weights. It is, however, also possible, that several different balance weights can be accommodated, which in particular means that the overall weight of the power adapter can be tuned, in particular fine-tuned, in particular in accordance with the weight distribution of the power tool to be used.

In cases, in which the housing is not fully filled with the balance weight or balance weight units, the housing has free spaces which may contribute to a more efficient cooling of the power tool, in particular if cooling is provided via the housing.

However, the balance weight is of great advantage, as the ordinary and usual weight distribution prevailing with conventional battery packs attached to the power tool, can be obtained, in particular simulated. It shall be noted, that the user in most of the cases is used to conventional weight distributions, and often, the weight distribution of the power tool is adapted under consideration of the weight of the battery pack.

The balancing weight or balancing weights themselves may be accommodated slidably within or on the housing. This may contribute to easily removing/exchanging the balance weights, in particular to adapt to different weight distribution requirements.

The power adapter may be connected, in particular fixedly or removably connected, to or with a cable connected to the energy source.

The power adapter, in particular the housing, is adapted to be coupled to a charging device, adapted to charge the energy source, in particular mobile energy source, such as a backpack energy source. In this way, the benefit of the power adapter is two-fold. On the one hand, the power adapter may be used to supply a power tool with energy of an external, in particular mobile energy source, while simulating battery-pack type conditions. On the other hand, the power adapter may be plugged from the power tool and, without any further actions, be plugged into the charging device. Here, time-saving operations may be obtained, in particular if interfaces of the power adapter, power tool and charging device are standardized.

The display may be any type of display, in particular <NUM>-segment displays, digital displays, LED-displays and the like. The advantages of a LED <NUM>-Segment-indication are the bright display, good visibility under working conditions, stable display in a wide temperature range and in particular the UV-stability.

Advantages of the proposed power adapter in particular are as follows. The proposed power adapter allows to use bigger portable battery-packs, in particular backpack batteries. In particular, the power adapter opens the possibility to use such a backpack battery for a variety of applications, in particular handheld power equipment, i.e. power tools, or handheld power tools. Additionally, different types of battery-packs can be used in the same application, in particular handheld power equipment. For example, the handheld power equipment may have an integrated battery-pack (10S2P-type). Since the dummy-battery has the same size, in particular outside geometry, and has the same interfaces, i.e. interface geometry (like that of 10S2P-type), the backpack battery can be used for respective handheld power equipment, too, leading to elongated operational times.

The power adapter according to the invention can be used with or within any electrically operated handheld devices, in particular within power tools such as hedge trimmers, clearing saws, chain saws, brush cutters, trimmers, blowers, screw drivers, drills, hammer drills, nailers, staplers, polishing or grinding tools, etc..

Preferred embodiments will now be described in connection with the annexed figures, in which:.

<FIG> shows a perspective and partially broken up view of a power adapter <NUM>. The power adapter <NUM> is to be inserted into a cordless hand-held power tool (not shown) and electrically and mechanically coupled to the cordless power tool for electrical supply of the power tool. The power adapter <NUM> comprises an adapter housing <NUM> in which a fixture unit (or: insert) <NUM> is accommodated, in particular inserted from above and slidably placed and/or removed from the housing <NUM>. When the fixture unit <NUM> is properly mounted inside the adapter housing <NUM>, the housing <NUM> is closed from above by a housing lid <NUM> which is fixed to the main part of the housing <NUM>, e.g. by means of screws as shown in <FIG> and <FIG>.

The fixture unit <NUM> without or outside of the adapter housing <NUM> is shown in <FIG>. Basically the fixture unit <NUM> comprises two halves or two fixture sub-units <NUM> and <NUM>, each preferably having a plate-like base structure and a number, in particular four, of fastening elements <NUM> and <NUM> respectively by which fastening elements <NUM> and <NUM> the fixture sub-units <NUM> and <NUM> are fastened to each other, in particular by snapping or shape-locking or also screws. In the assembled or fastened state the two fixture sub-units <NUM> and <NUM> and the fastening elements <NUM> and <NUM> form a box-like or framelike fixture unit <NUM> and enclose an inner space <NUM> of the fixture unit <NUM>.

The power adapter <NUM> comprises a contact and coupling electrical interface <NUM> adapted to be coupled to a respective counter interface of a cordless power tool (not shown).

In the inner space <NUM> of the fixture unit <NUM> it is, in a direct powering operation, possible to arrange battery cells (not shown) to electrically power the power tool directly from the power adapter <NUM> through the electrical interface <NUM> of the power adapter <NUM> being electrically coupled with a corresponding interface (not shown) of the power tool when the power adapter <NUM> is mounted in the power tool.

In order to insert or replace batteries the fixture unit <NUM> is dismounted from the housing <NUM> and the two fixture sub-units <NUM> and <NUM> are disassembled so that the batteries or new batteries can be mounted in between the fixture sub-units <NUM> and <NUM> or first in one of them. For this purpose a receiving space <NUM> (or <NUM>) is provided at one or both of the fixture sub-units <NUM> and <NUM> being formed by a surrounding side wall <NUM> (or <NUM> [not indicated in the figures]), so that the batteries are inserted into the receiving space <NUM> (or <NUM>) and held by the side wall <NUM> (or <NUM>). The fixture sub-units <NUM> and <NUM> can be re-assembled and fixed by means of the fastening elements <NUM> and <NUM> again. Preferably, both side walls <NUM> and <NUM> of the receiving spaces <NUM> and <NUM> can hold or support the batteries in the power adapter <NUM> and are, for this purpose, opposing each other when the two fixture sub-units <NUM> and <NUM> are mounted to form the fixture unit <NUM>.

However, when external batteries such as backpack battery assemblies to be carried on the back of the user of the power tool are used for electric supply of the power tool the power adapter <NUM> does not need to comprise batteries by itself. Rather, the power adapter <NUM> in this case is connected to the external batteries by means of a cable <NUM> on one hand and by its electrical interface <NUM> to the power tool <NUM> on the other hand. In this indirect powering operation case the power adapter <NUM> has only the passive function of electrically connecting the power tool with the external batteries, in particular backpack batteries. For the user it is somewhat like a dummy battery.

Now, the mass distribution and weight of a power tool is usually balanced for an optimum use and for this balancing the considerable weight of the batteries inside the power tool is taken into account.

However, in the indirect powering operation the power adapter <NUM> has no batteries and thus lacks the weight it has in the direct powering operation. This can lead to an unpleasant and different behaviour of the power tool during indirect powering operation as compared to direct powering operation.

To compensate this disadvantage a counter-weight or balancing weight <NUM> is provided in the power adapter <NUM> to reach at least approximately the same weight and balance of the power tool as if batteries were present. So, preferably for each power tool and battery set a corresponding set of balancing weights can be provided.

Preferably, the balancing weight <NUM> is arranged in the same region of the power adapter <NUM>, i.e. here the inner space <NUM> of the fixture unit <NUM>, where in the direct powering operation the batteries would be placed so as to emulate or produce the same balancing behaviour as if the batteries were present in the same place. In this case the balancing weight <NUM> can have basically the same mass as the (missing, replaced) batteries.

A preferred embodiment of how to incorporate the balancing weight <NUM> in the power adapter <NUM> is shown in <FIG>. Here, the balancing weight <NUM> which is shown only partly in a partially sectioned view, is received within the receiving space <NUM> surrounded by the side wall <NUM> and the base plate at the bottom of the first fixture sub-unit <NUM>. For instance the balancing weight <NUM> can be a mineral body such as concrete or any other material such as metal or a compound material of metal and mineral or plastic or resin material which is heavy enough to reach the weight of the missing batteries. The weight <NUM> can be produced in situ into the receiving space <NUM> for instance poured into it or produced separately and then fixed into the receiving space <NUM> for instance by press-fitting or shape-locking or glueing or any other suitable fastening means. By means of the density and the size of the weight <NUM> the weight of the missing batteries in the power adapter <NUM> can be compensated.

This embodiment has the big advantage that only the first fixture sub-unit <NUM> has to be changed or replaced when the power adapter <NUM> is to be used in indirect powering operation instead of direct powering operation. The second fixture sub-unit <NUM> and all other components of the power adapter <NUM> as well as its dimensions and mechanical interfaces and electrical interface <NUM> to the power tool can basically stay the same.

In an alternative embodiment both fixture sub-units <NUM> and <NUM> have a balancing weight <NUM> and, thus, are both replaced in the case of direct powering operation or, in other words, the whole fixation unit <NUM> is replaced by a fixation unit having batteries instead.

Balance weights <NUM> of different types, in particular different weight can be attached to the fixture unit <NUM>. Preferably, the fixture unit <NUM> and balancing weight <NUM> of different types are designed such that the outer geometry of the fixture unit <NUM> with the balancing weight <NUM>, is independent from the type of balancing weight <NUM>, and can in any case be inserted into the housing <NUM>.

Providing the balancing weight <NUM>, in particular with the fixture unit <NUM>, has the advantage that the weight of the power adapter <NUM>, as such being clearly lighter than conventional NiMH or Li-Ion accumulator packs, can be adapted to match, in particular approximately match, the weight of the conventional battery packs. This in turn has the advantage that a favorable balance of weight can be obtained, which is or will be familiar to a user experienced in operating battery-pack driven tools. The power adapter <NUM> therefore simulates the presence of a conventional battery pack.

However, as the power adapter <NUM> can be connected to a remote battery pack, such as a backpack battery pack, as will be described further below, a battery pack of comparatively high load capacity can be used and the overall operational time can be raised.

As shown in <FIG> and <FIG> the power adapter <NUM> also comprises a display unit <NUM>. The display unit <NUM> is adapted and attached in such a way that, in an indirect powering operation, the loading or charge status and/or temperature of a remote, movable energy source, such as a backpack battery pack, can be displayed and observed by a user during operation of the power tool. Such a display unit <NUM> is of particular advantage for backpack battery packs, as the loading status of the battery pack on the back of the user in this way can be easily checked during operation of a tool connected to the energy source and power adapter <NUM>. Signals for controlling the display unit may be outputted from an electronic controller or the like of the energy source. Of course it is also possible that the display unit <NUM> shows the charge status and/or temperature of batteries inside the power adapter <NUM> in a direct powering operation, in particular when the first fixture sub-unit <NUM> with the weight <NUM> is replaced by a sub-unit adapted for batteries.

Furthermore, the power adapter <NUM> may comprise a slewable cable outlet <NUM>. The slewable cable outlet <NUM> has an outlet opening <NUM>. The outlet opening <NUM> is adapted to guide through an electric cable (shown in <FIG> only) for connecting the power adapter <NUM>, in particular electrical contacts of the coupling interface of the power adapter <NUM>, to a remote energy source, such as a backpack battery pack.

The slewable cable outlet <NUM> may comprise or be constituted by a slewable member attached and mounted to the housing <NUM> to be slewable as indicated by the double arrow in <FIG>. In <FIG>, the slewable member is slewable in a horizontal plane. However, it is also or in the alternative possible to implement the slewable member to be slewable in a vertical plane. Such a slewable member will greatly ease operation of a tool or device connected to the power adapter <NUM> since the cable has a slewing range of up to <NUM>° in a rotational movement. Of course also a spherical movement is possible, i.e. a rotation about two orthogonal axes.

Also the housing <NUM> comprises air vents <NUM> which allow a flow of air through the housing <NUM> which is not completely, in particular only slightly, filled. As can be seen, despite of the balance weight <NUM> and fixture unit <NUM> accommodated in the housing <NUM>, the housing <NUM> still comprises a dead volume. This dead volume may contribute to enhanced air flow which may be used to cool the tool or device operated via the power adapter <NUM>. So the cooling of the electronic components in the power adapter <NUM> and of the power tool <NUM> is improved.

In <FIG> an embodiment of the whole system including a power tool <NUM> with a power adapter <NUM> and an external battery supply, here a backpack battery assembly <NUM>, is shown. The power adapter <NUM> has an electrical cable <NUM> exiting from its cable outlet <NUM> which electrical cable <NUM> is electrically connected through an electrical connector <NUM>, in particular a magnetic or a plug-socket-connector, to an electrical cable <NUM> of a backpack battery assembly <NUM> to be carried on the back of a user while the user holds the power tool <NUM> in his hands. The power adapter <NUM> is for illustration purposes not yet inserted into the power tool <NUM>. Although the power adapter <NUM> has a cord or cable for connection to the batteries, the power tool <NUM> itself remains a cordless power tool. In particular the cable will be carried by the user and not fall on the ground, nor and more important will the length of the cables <NUM> and <NUM> restrict the range of the power tool <NUM> thus maintaining the mobility of a cordless battery powered power tool.

<FIG> shows an exploded view of a further embodiment of the power adapter <NUM> according to the invention. The power adapter <NUM> in this configuration comprises a base section <NUM> and a corresponding dome shaped cover <NUM>. The base section <NUM> and cover <NUM> can be connected to each other, in the present case via screws <NUM>, to establish a casing or housing adapted for accommodating elements or components of the power adapter <NUM>.

Elements or components accommodated within the casing are as follows: a support plate <NUM> adapted for supporting a balancing weight <NUM> on the base section <NUM>, and a retaining bracket <NUM> adapted for retaining and holding the balancing weight <NUM> on the base section <NUM>. The bracket <NUM> at least partially embraces the balancing weight <NUM> and is adapted to be fixed to the base section <NUM>, presently via further screws <NUM>, optionally via shape-locking elements or connections and the like.

As can be seen from <FIG>, the bracket <NUM> comprises on a side averted from the support plate <NUM> a cable clamp arrangement <NUM> adapted to tightly clamp cables such as for example a cable <NUM> for electric power supply.

The cable <NUM> is guided through the base section <NUM>, through the inner of the casing and finally ends in a connector interface <NUM> adapted to establish electric contact and others to corresponding counter contacts of the cordless power tool.

As already becomes obvious from <FIG>, the power adapter <NUM> in this configuration enables comparatively compact arrangements and designs of the elements arranged or accommodated within the casing. In particular beyond the balancing weight <NUM> and bracket <NUM> there is still room left for guiding cables, such as cable <NUM>, and air ventilation through the casing.

As can also be seen from <FIG>, the base section <NUM> comprises a cable bushing <NUM>. The cable bushing <NUM> is implemented as a funnel shaped element extending from the base section <NUM> to the inner volume of the casing. As will become more obvious further below, the outer walls of the bushing <NUM> are designed to implement a funnel or cone having increasing cross sections in a direction from the inside of the casing towards its outside. Using such a funnel shaped cable bushing <NUM> has the advantage that the cable bending radii of the cable <NUM> can be kept at moderate values during operation or use of the power adapter <NUM>. In particular too small bending radii probably causing cable damages may be avoided, at least at the cable bushing <NUM>. Also, less space is needed to align the cable along the outside surface of the adapter or powertool.

<FIG> shows the base section <NUM> of the power adapter <NUM> in more detail. The base section <NUM> has an essentially rectangular shape and provides several elements for fixing the cover <NUM>, bracket <NUM> and others. Further, the base section <NUM> may comprise at its inner side several reinforcement elements or ribs. However, the base section <NUM> of the present embodiment comprises a recess <NUM> which is adapted to accommodate a printed circuit board, in particular in a press-locking, shape-locking and/or snap-locking manner. The PCB may also be fastened by means of screws for example. Several support elements for supporting the printed circuit board are arranged in the recess <NUM>.

<FIG> shows the base section <NUM> with the printed circuit board arranged within the recess <NUM>, wherein the printed circuit board is designated with reference number <NUM>. Mounting the printed circuit board within the base section <NUM> has the advantage that it can be protected against outer mechanical impacts, as the base section <NUM> is of comparative robust construction. Further, display and/or operating elements <NUM> (<FIG>) or signs related to the printed circuit board <NUM> may be viewed through the base section <NUM>, which in general is visible even if the power adapter <NUM> is coupled to a cordless power tool.

As has been described in connection with <FIG>, the balancing weight is also mounted or fixed to the base section <NUM>. As becomes clear from a combination of <FIG>, the location of the printed circuit board <NUM> in the base section <NUM> at least overlaps with the mounting location of the balancing weight <NUM>. In order to avoid the balancing weight <NUM> to directly rest on the printed circuit board <NUM>, the base section <NUM> comprises several support ribs <NUM> adjacent to the recess <NUM>. The support ribs <NUM> are adapted and configured such that they can support the support plate <NUM>, and in particular can engage corresponding grooves or notches or ribs provided with the support plate <NUM>.

Reference is now made to <FIG> showing the base section <NUM> together with the support plate <NUM> in a configuration suitable for supporting the balancing weight <NUM>. It shall be noted, that the printed circuit board <NUM> is not visible in <FIG>. This is due to the fact, that in the present embodiment, the recess <NUM> accommodating the printed circuit board <NUM> is potted or sealed with a potting or sealing compound <NUM>, which is provided for protecting the printed circuit board <NUM> from outer influences.

Further, the support plate <NUM> connected to the base section <NUM> comprises or provides support bars <NUM> adapted to support the balancing weight <NUM> placed on the support plate <NUM>. A respective arrangement of the balancing weight <NUM> on the support plate <NUM> can be seen in <FIG>. From <FIG> it can in particular be seen that the support plate <NUM> fully supports the load of the balancing weight <NUM> and thereby prevents the load of the balancing weight <NUM> from acting on the printed circuit board <NUM> and/or potting or sealing compound <NUM>.

Reference is now made to <FIG> showing the balancing weight <NUM> attached or fixed to the base section <NUM> via the retaining bracket <NUM>. The retaining bracket <NUM> in the present case is screw-mounted to the base section <NUM>. Further, the retaining bracket <NUM> comprises stiffening elements, such as stiffening ribs, configured to firmly fix the balancing weight <NUM> to the base section <NUM> in particular in extreme situations, in particular in situations in which the power adapter crashes, unintentionally, to the ground and the like.

In <FIG> it can be seen that the retaining bracket <NUM> comprises at lateral sides, in the present case at two lateral sides averted from each other, a respective support jib <NUM>. The support jibs <NUM> are designed such that the retaining bracket <NUM> is and will be supported against the inner walls of the cover <NUM> in case that the base section <NUM> and the cover <NUM> are connected to each other. The support jibs <NUM> may be effective in preventing cracking or rupturing the retaining bracket <NUM> and balancing weight <NUM> from the base section <NUM> under extreme loads, such for example occuring in instances where the power adapter, unintentionally, or in drop tests, crashes or is crashed to the ground.

As can be seen in more detail from <FIG>, the support jigs <NUM> can have a secondary function in which the support jigs <NUM> are used for cable routing, as a cable holder and/or a cable retainer for the cable <NUM> or cables or other elements within the casing which is assembled from the base section <NUM> and cover <NUM> connected thereto.

<FIG> further shows that there is still room left within the casing which in particular is advantageous for allowing an air flow through the casing, in particular for cooling respective components accommodated therein.

<FIG> shows the power adapter <NUM> in an advanced preassembled state in which the printed circuit board <NUM> is potted to the base section <NUM> and the balancing weight <NUM> is fixed to the base section <NUM> via the retaining bracket <NUM>. Further, the cable <NUM> or parts thereof are fixed to respective retaining elements, in particular to the cable clamp arrangement <NUM> and support jib <NUM>. The connector interface <NUM> is adequately mounted to the base section <NUM>, and the snap locking elements <NUM> are connected to the base section <NUM>.

In this state of assembly, the cover <NUM> can be imposed or put on the base section <NUM> and all elements assembled thereto, and the cover <NUM> can be fixed to the base section <NUM>.

Here, it can in particular be seen that the proposed embodiment allows a great deal of preassembly work on the basis of the base section <NUM>. In a final assembly step only the cover <NUM> may be connected, which in particular is indicated in <FIG> by arrows.

<FIG> shows the power adapter in the assembled state. From <FIG> it can be seen that the cover <NUM> comprises air vents <NUM> allowing a cooling airflow through the casing. Further, it can be seen that the display and/or operating element or unit <NUM> is freely accessible and visible even if the power adapter <NUM> should be connected to a power tool.

It can also be seen from <FIG>, that the base section <NUM> may be screw mounted to the cover <NUM>.

Reference is now made to <FIG> showing a different perspective view of the power adapter <NUM> in <FIG>. As can be seen from a combination of <FIG> and <FIG>, the cable bushing <NUM> is implemented as a funnel or cone shaped deepening providing convex outer walls for reducing or restricting the bending radii of the cable <NUM> during operation to moderate values. The bending radii in particular are selected such that damages to the cable <NUM> as a result of sharp bends at the cable bushing <NUM> can be avoided, and such that bending of the cable in a certain direction is facilitated.

Claim 1:
Energy source and power tool combination comprising
- a cordless hand-held power tool (<NUM>);
- a backpack battery assembly (<NUM>) specially adapted to be carried on the back of the user via at least one shoulder strap;
- a power adapter (<NUM>);
- an electrical cable (<NUM>, <NUM>) interconnecting the backpack battery assembly (<NUM>) and the power adapter (<NUM>); wherein
the power adapter (<NUM>) is configured to be mounted in the power tool (<NUM>) and electrically coupled with a corresponding interface of the power tool (<NUM>) when the power adapter (<NUM>) is mounted in the power tool; the combination being characterized by that the power adapter (<NUM>) is adapted to be connected to a charging device for charging the backpack battery assembly (<NUM>), wherein the combination further comprises a rechargeable battery pack with the design and dimensions corresponding to a housing of the power adapter (<NUM>), wherein the power adapter (<NUM>) comprises a removable balance weight (<NUM>) providing the ordinary weight distribution of the rechargeable battery pack.