NL2015937B1

NL2015937B1 - Power tool.

Info

Publication number: NL2015937B1
Application number: NL2015937A
Authority: NL
Inventors: Dijkgraaf Olaf; Joore Rick
Original assignee: Bosch Gmbh Robert
Priority date: 2015-12-10
Filing date: 2015-12-10
Publication date: 2017-07-03
Also published as: NL2015937A

Abstract

The invention relates to a Power tool. The power tool comprises a housing, accommodating a motor, a user operable motor actuator and a chargeable battery. Furthermore the power tool comprises a connector configured for connection of the battery to a battery charging power supply and a selector configured to selectively connect the battery with either the motor or the power supply.

Description

POWER TOOL

The present disclosure relates to a power tool, in particular a portable power tool.

The inventors of the present disclosure are aware of prior art portable power tools with external battery packs, where the battery packs are to be carried by a user / operator.

Additionally, the inventors of the present disclosure are aware of prior art portable power tools, that have an accommodation in, on or against a housing thereof for batteries or a battery pack. Often, batteries or battery packs are replaceable for recharging in a separate charger. When a battery or battery pack is depleted of sufficient electrical charge to continue operating the tool, another fully charged battery may be inserted into the power tool, or otherwise electrically connected therewith, to continue working with the power tool.

The latter named prior art power tools exhibit considerable disadvantages. In public opinion, a second battery is considered almost indispensable, to have one battery in operation and another in a separate charger, so as to be able to continue working as long as possible. However, this required duplicate batteries for a single power tool with disadvantageous environmental consequences. Moreover, costs are increased, for all of manufacturers, merchants, DIY shops and end consumers and the like.

The present disclosure has for an object to decrease or even mitigate aforementioned or other disadvantages of the prior art power tools, to which end is proposed: a power tool, comprising: a housing, accommodating a motor, a user operable motor actuator and a chargeable battery; and a connector configured for connection of the battery to a battery charging power supply; and a selector configured to selectively connect the battery with either the motor or the power supply.

According to such a configuration of a power tool, a second battery can be omitted, contrary to public prejudice that a second battery is considered indispensable. The reason is that power tools are seldom used continuously. For example, when using a motor screw driver, time between driving subsequent screws may be used for replenishing spent charge or load of the battery. A power connection cable preferably remains connected to the power tool, but the present disclosure also enables cordless operation of the power tool, for example if a length of a power cable is insufficient to reach a work location. In any case, operation based on the battery is mostly preferred because of the superior current characteristics of batteries, relative to current supply from a mains connection. Thus the present disclosure enables the power tool to operate based on power for the motor from the battery, when the power tool is in use, and charge the battery in periods during which the power tool is intermittently inoperative.

Within the breadth and width of the general concept of the present disclosure, as set out herein above and as defined in the appended independent claim, many are possible, as set out below and defined in the appended claims. It is to be emphasized here that the present disclosure is by no means limited to any particular exemplary embodiment, and that a boundary of the scope of protection for the present disclosure can only result from limitations in the appended independent claim and includes equivalents of such particularly claimed features.

More in particular, the present disclosure encompasses an embodiment, further comprising a detector, which is responsive to user operation of the motor actuator to selectively generate a motor actuator operation signal, and a control, which is responsive to the motor actuator operation signal to drive the selector for connection of the battery to the motor. Thus switching between operation of the power tool and charging of the battery is based on automatic detection, and ease of use is enhanced for the user / operator of the power tool. In such an embodiment, the detector may comprise a micro switch associated with the motor actuator. This enables convenient detection in a practically mechanical way, of operation of the tool by detecting operation of the actuator. However, electrical or electronic alternative solutions of enabling such functionality are also within the realm of possibilities within the scope of the present disclosure. With a detector and a control, which may be integrated into a single element or component or circuit, the motor actuator may comprise a user operable trigger. Triggers are known per se, but the combination thereof with a detector and a control in general, or with a switch, such as a micro-switch enables a very simple and elegant solution to detection of operation of the power tool, to end charging and enable supply of power from the battery to the motor.

In addition or alternatively, the present disclosure may encompass a power tool, further comprising a battery charging printed circuit board between the selector and the connector. This is in conjunction, for example, with a Lithium-Ion (Li-Ion) battery or other type of battery, which requires setting or regulation of a particular charging current or voltage relative to the power supply of for example a mains supply. It is to be noted in this respect that Li-Ion batteries are far less susceptible to a memory effect, than for example cadmium batteries, and are consequently particularly suitable to be applied in a power tool according to the present disclosure, which aims at keeping a battery constantly as full as possible.

In addition or alternatively, the present disclosure may encompass a power tool, wherein the motor actuator comprises an arm, extending towards the selector, to operate the selector depending on an instantaneous position of the motor actuator. Thus a highly reliable mechanical solution is provided for relaying operation of the motor actuator to setting of the selector.

In addition or alternatively, the present disclosure may encompass a power tool, wherein the battery is integrated in the housing. As the present disclosure obviates a need to replace a depleted rechargeable battery with a fully charged one, the battery may be integrated into the housing of the power tool. This enables the battery or battery pack to be positioned or even distributed in the housing to achieve a far better weight distribution, for example from an ergonomic point of view.

In addition or alternatively, the present disclosure may encompass a power tool, wherein the connector is essentially continuously and conductively coupled with the power supply via a cable. This enables constant charging, or at least in periods of non-operation of the power tool. In such an embodiment, the cable may comprise a power plug for coupling with the connector, and the housing comprises a cable or plug holder. Such a cable or plug holder may be useful to prevent the cable from being removed from an electrically conductive connection to the power tool.

In addition or alternatively, the present disclosure may encompass a power tool, wherein a battery charger is separate from the housing and connected with the battery via a charger cable. Alternatively, the charger may be in the housing, with a cable running from a mains outlet to the poser tool and more in particular to the charger in the interior of the housing, for conversion into a desired voltage or current characteristic and transmission to the battery for charging thereof. In any case, the power tool preferably has a cordless operation mode, and a wired operation mode for charging the battery in intermittent periods when the power tool is inoperative.

Following the above reference to aspects of the present disclosure in more generic terms, corresponding with the features defined in the appended claims, herein below embodiments will be described in more specific terms and referring to more particular features, to further elucidate the present disclosure. However, none of the preferred embodiments are to be interpreted as limiting on the scope of protection according to the present disclosure. The following embodiment description relies on the appended drawings, in which reference signs are included for convenience of the reader, where the same or similar reference signs may be employed when referring to distinct embodiments. In the drawing:

Figure 1 shows a partly open view of an exemplary power tool according to the present disclosure;

Figures 2-5 show subsequent steps when depressing a trigger of the power tool; and

Figures 6, 7 show schematic representations of circuits of a charger PCB and a LED driver circuit.

The power tool 1 in figure 1 comprises a housing 2. The housing 2 accommodates a motor 10, a user operable motor actuator in the form of a user operable trigger 8 with a controller 7 and a chargeable battery pack 3. The housing comprises a light source, for example a LED light source 6, of which a driver circuit is shown in figure 7. At least when the motor 10 is driven, the LED 6 may be turned on.

Further, the power tool 1 comprises a connector in the form of socket 4, which is configured for connection of the battery pack 3 to a battery charging power supply, such as a mains outlet (not shown) via a cable having a plug at a free end thereof (not shown). The housing may comprise a converter to deliver a suitable voltage or current for charging the battery pack 3. Alternatively, the converter may have a form of a casing to be plugged into a mains outlet with the cable extending from the casing to the socket 4 of the power tool 1.

Further, the power tool comprises a selector comprising a micro switch 9 and controller 7. Controller 7 or an alternative component is configured to selectively connect the battery pack 3 with either the motor 10 for effective use of the tool 1 or to the power supply via the socket 4 for charging of the battery pack 3.

In this manner, according to the present disclosure, the power tool 1 comprises a detector formed by the micro switch 9 and the controller 7 (or another suitable component). The situation in which trigger 8 is not (yet) depressed, is shown in figure 2. The detector is responsive to user operation of the motor actuator in the form of the trigger 8, to selectively generate a motor actuator operation signal, by detection when the trigger is starting to being depressed, as shown in figure 3. When the trigger is being depressed, the motor actuator operation signal is generated, and the control 7 is responsive to the motor actuator operation signal to connect the battery pack 3 to the motor 10. Beforehand the battery is connected to the cable for charging from an external source, such as a charger or the mains outlet. Further depression of the trigger 8 as shown in Figure 4 results in connection of the battery pack 3 to the motor 10 via a resistive conductor 13, with which a force or rotational speed of the motor 10 can be set, for effective use of the power tool, for example for driving screws into a work piece, such as a wall, at variable torque or speed or the like, depending on the degree of depression of the trigger 8. When the deepest depression of trigger 8 is reached, as shown in figure 5, motor 10 is at maximum rotational speed, torque or the like. For example, in a simplified version, resistive conductor 13 can be arranged on a cylinder 14 to be covered less or more by a bus 16, depending on a degree of depression of the trigger 8, which can determine the motor output in terms of speed, torque or the like.

The motor actuator in the form of trigger 8 or an alternative embodiment, may comprise an arm 17 acting on a lever contact 15, when the trigger is in the foremost position thereof (figure 2). The arm extends towards the micro switch 9 and more in particular towards the lever contact 15. In this way contact can be established or broken, depending on position of the trigger 8. The lever contact 15 in the positions thereof according to figures 3, 4 and 5 will operate to generate the motor actuator operation signal. Even absence of any particular voltage or current may form such a motor actuator operation signal.

The power tool 1 also comprises comprising a battery charging printed circuit board (PCB) 5 between the battery pack 3 and the connector 4. The PCB 5 can comprise circuitry, for example as in figure 6, configured to adjust charging voltage and/or current from a charger (not shown), for instance depending on ambient temperature, instantaneous charging or load characteristics and the like. Also, the PCB 5 may itself form a charger.

The battery pack 3 preferably comprises at least one Li-Ion or similar battery, which is less prone to adverse effects of a memory phenomenon. Since the battery pack 3 is to be charged, whenever the power tool is not actually in use, the battery pack 3 can be at or near full charge constantly, as long as the power tool is connected to a mains outlet or a charger via the aforementioned cable.

Since the battery pack 3 will hardly ever approach depletion, if used according to the intentions of the present disclosure, it is not necessary to provide an end user with a second chargeable battery, and the battery pack 3 may be integrated in the housing 2.

Based on the above described features of a power tool according to the present disclosure, the skilled person will immediately realise that many alternatives and equivalents for specifically described and claimed features are within the breadth and width or scope of the present disclosure. All such additional and/or alternative embodiments lie within the scope of protection according to the present disclosure, and the present disclosure is by no means to be interpreted as limited by or to any particular feature of the exemplary embodiments described above under reference to the appended drawing.

Claims

Electric power tool, comprising: - a housing, in which a motor, a motor-operated actuator and a rechargeable battery are accommodated; - a connection configured for connecting the battery to a battery charging power supply; - a selector, which is configured for selectively connecting the battery to one of the motor and the power supply.

The power tool of claim 1, further comprising a detector responsive to operation by the user of the motor actuator to selectively generate an operating signal from the motor actuator, and a controller responsive to the operating signal from the motor actuator about the selector for connecting the battery to the motor.

The power tool of claim 2, wherein the detector comprises a micro switch associated with the motor actuator.

A power tool according to claim 2 or 3, wherein the motor actuator comprises a tractor to be operated by a user.

A power tool according to any one or more of the preceding claims, further comprising a battery charging PCB (printed circuit board) between the selector and the connection.

The power tool of claim 5, wherein the battery comprises a Li-Ion battery.

A power tool according to any one or more of the preceding claims, wherein the motor actuator comprises an arm extending toward the selector to operate the selector in dependence on an istantane position of the motor actuator.

A power tool according to any one or more of the preceding claims, wherein the battery is integrated in the housing.

9. Power tool according to any one or more of the preceding claims, wherein the connection is connected substantially continuously and conductively via a cable to the power supply.

The power tool of claim 9, wherein the cable comprises a power supply plug for coupling to the connection, and wherein the housing comprises a cable or a plug holder.

A power tool according to any one or more of the preceding claims, wherein a battery charger is separate from the housing and is connected to the battery via a charging cable.