The invention relates to an indication device for a power tool.

Specifically, the invention relates to an indication device that has an improved visibility.

Background

Power tools such as nutrunners or screw drivers are getting more and more sophisticated. Conventional industrial power tools of today are provided with sensors, such as angle encoders and/or torque meters, which make it possible to control the quality of a performed work operation, such as the tightening of a joint. Many power tools are therefore provided with some kind of indication device arranged to signal to the operator whether a performed work operation was OK or NOK. Typically a successful work operation (OK) can be indicated by means of a green light and an unsuccessful work operation (NOK) can be indicated by means of a red light.

A problem with conventional indication devices is the location of the indication device. Namely, during operation the operator may need to keep the eyes focused on the work piece such that he may not be able to react on the given light indication. This may also be due to that the indication device is located on a part of the tool that may not b< viewable for the operator in a certain working position.

Hence, there is a need for an indication device that is reliable and that has a an improved visibility, such that the signal of the indication device is visible in different tool positions.

Summary of the invention

An object of the invention is to provide an indication device with improved visibility over a wide angle interval. This object is achieved by the invention according to claim 1, which relates to an indication device for a power tool, comprising a casing, an electric light source, and at least one light transmitting lens. The indication device further comprises a reflector in which the electric light source is at least partly comprised, wherein the at least one lens has a planar shape extending from an inner surface facing a light emitting portion of the reflector to an outer surface adapted to extend through at least one slot shaped opening in the casing, wherein the at least one lens is arranged to emit light in multiple directions which are separated by an angle of at least 90 degrees along the casing to provide a light signal that is visible from a wide range. The light emitting portion of the reflector is aligned with the slot shaped opening of the casing.

With the invention one single light source may be arranged to provide a light in a wide angular range. The planar shape of the lens will make sure that the light is transmitted with as little losses as possible from the light emitting portion of the reflector to the outer surface of the lens, as the light will be reflected by the planar surfaces of the lens . In one embodiment the lens is arranged to emit light in multiple directions which are separated by an angle of at least 150° along the casing. This embodiment further improves the visibility, such that the light from the indication device may be seen practically all sides of the indication device. In a specific embodiment the indication device comprises only one light transmitting lens, wherein the outer surface of said lens is arc shaped and extends continuously over an angle of at least 150° of the casing. It is beneficial to have a construction that allows a single lens to spread the light in multiple directions . In another specific embodiment the indication device comprises at least two light transmitting lenses that emit light through at least two angularly separated slot shaped openings in the casing. A purpose of having more than one lens is to improve the strength of the construction by means of casing parts arranged between the lenses to connect the top and bottom parts of the casing. In a specific

embodiment the indication device comprises two light transmitting lenses that each extend continuously over an angle of at least 120° of the casing.

In a specific embodiment the indication means indication device is puck-shaped, wherein the casing has a substantially flat portion covering one side of the indication device, and a connection portion on the opposite side of the signalling piece for connecting the indication device to a power tool housing.

In another specific embodiment the casing includes a central recess on the inside of a flat portion into which an upper part of the reflector fits tightly, and wherein the connection between the lens and the reflector mutually locks the lens and the reflector from movement inside the casing. This construction is advantageous as it permits the structure to be held together without screws or fasteners, which yields a simple, compact and reliable construction.

In yet another embodiment the light emitting portion of the reflector is comprised of a thin walled segment. This is advantageous as it helps produce a soft even light along the whole periphery of the lens.

Further, in another specific embodiment the electric light source is not located in said alignment between the light emitting portion of the reflector and the slot shaped opening of the casing, such that that only reflected light will be emitted through the lens. This is advantageous as it helps produce a soft even light along the whole periphery of the lens, because no light will be directly emitted from the light source to the outer surface of the lens .

In one embodiment the reflector is snap fitted onto a circuit board that includes the electric light source, such that the electric light source is comprised inside the reflector. This construction is advantageous as it permits the whole structure of the indication device to be held together without screws or fasteners, which yields a simple, compact and reliable construction.

Other features and advantages of the invention will be apparent from the figures and from the detailed description of the shown embodiment.

Short description of the drawings

In the following detailed description reference is made to the accompanying drawings, of which:

Fig. 1 shows an end portion of a power tool provided with an

indication device according to a specific embodiment of the invention;

Fig. 2 shows an exploded view of the indication device of fig. 1;

Fig. 3 shows a cross sectional view of the indication device of fig. 1 ; and

Fig. 4 shows a longitudinal sectional view of the indication device of fig. 1.

Detailed description of the shown embodiment

In fig. 1 an end portion of a power tool 10 provided with an

indication device 11 according to a specific embodiment of the invention is shown in side view. As is visible from the view of fig. 1 the indication device 11 comprises a casing 12, and a light

transmitting lens 14.

In fig. 2 the indication device 11 is shown in an exploded view, such that the interior parts of the indication device 11 are visible.

The indication device 11 includes a light source 13, such as a LED. A reflector 15 is arranged to house the light source 13. The light source 13 is in the shown embodiment arranged on a circuit board 20, which is connectable via a connector 21 to voltage source inside the housing of the tool. The circuit board 20 is adapted to be fastened to the reflector via a snap connection including snap connectors 22 on the reflector 15 that are arranged to snap around a waist 23 on the circuit board 20.

The reflector 15 has an internal space 24 adapted to house the light source. In the shown embodiment, the reflector 15 has a light emitting portion 17 that extends over about 180° of its wall. In the shown embodiment the light emitting portion 17 consists of a thin, light permeable wall. This has the advantage of making the outgoing light even. Further, of course, it improves the durability of the reflector. It would of course also be feasible that the light emitting portion 17 would consist of a void in the form of a slot shaped opening. Either way, the light emitting portion 17 may be arranged to extend over a lesser angle than 180°. In order to have the signal visible from many different angles of the tool it would be preferred to have an

extension of at least 90°, or to have the light emitted in angularly separated segments that provides a total visibility of the signals over an angular spread of at least 90°, and preferably at least 150°. However, in fact, in an embodiment with a plurality of separated light emitting lenses light could be emitted in segmented intervals over the entire periphery of the casing 12 of the indication device 11. The mechanical strength of the casing and reflector could in such a case be provided by adjoining parts between the angularly separated light emitting segments .

The reflector 15 has a top part 25 and a cylindrical, or part

cylindrical, portion 31 in which the light emitting portion 17 is arranged. The reflector 15 is in its simplest form made of a single piece, preferably a white plastic piece. White is advantageous as it reflects light in a good way at the same time as it allows most of the light to pass through a thin walled portion, such as the light emitting portion 17. In a more complex embodiment of the invention the inner walls of the reflector, apart from the light emitting portion 17, are provided with a light reflecting foil or layer in order to lessen losses and to further improve the productive light emission through the lens or lenses .

The lens 14 has a planar shape extending from an inner surface 16 facing the light emitting portion 17 of the reflector 15 to a rounded outer surface 18 adapted to extend through a slot shaped opening 19 of the casing 12 that extends over an angle of at least 90° of the casing 12 to provide a rounded slot shaped light signal. In similarity with the shape of the light emitting portion 17 of the reflector 15 the slot shaped opening 19 may extend over about 180° as in the shown embodiment or over segmented intervals over an angular spread of at least 90°, and preferably around 180°, and possibly up to 360°.

In the shown embodiment the reflector 15, the lens 14 and the casing 12 are form fitted to each other. The casing 12 includes a recess 26 adapted to receive the top 25 of the reflector 15. See fig. 4. When the reflector is at place inside said recess 26 the lens 14 may be pushed through the slot shaped opening 19 into contact with the reflector 15, such that the inner surface 16 of the lens 14 comes into contact with or close to the light emitting portion 17 of the

reflector 15. As mentioned above the circuit board 20 including the light source 13 may be snapped into connection with the reflector 15. Hence, the indication device 11 may be handled as one unit which may be fastened to a power tool 10 as soon as the circuit board 20 has been connected to the voltage source of the power tool via the connector 21. As is shown in figure 3 the casing includes two screw holes 27 which are arranged to fasten the indication device 11 to a power tool, wherein the power tool is provided with matching threaded screw holes . The screw holes 27 through the casing 12 are preferably unthreaded. As is further visible in fig. 3 the lens 14 comprises a recess 28 in which a tool such as a screw driver may be inserted in order to separate the lens 14 from the reflector 15. As is visible in fig. 4 the casing 12 includes a connection rim 29, which is adapted to fit tightly inside the housing of the power tool. In fig. 4 it is also apparent that the light source 13 is arranged below the light emitting portion 17 of the reflector 15. The fact that the light source is not located in line with the lens 14 is useful in that it will make sure that the light that will be emitted from the lens 14 will have an even distribution along the whole rounded outer surface 18 of the lens 14. In the shown embodiment there is thin gap 30 between the inner surface 16 of the lens 14 and the light emitting portion 17 of the reflector 15. This gap 30 may be omitted and merely exists to provide a production play in order to make sure that the parts fit together.

The light source 13 is preferably a LED (Light Emitting Diode) but may be any type of light source that is known in the art. It is

advantageous if the light source may emit different colours, such as blue, green, red, and white such that different signals may be produced in the same lens .

Above, the invention has been described with reference to a specific embodiment. The invention is however not limited to this embodiment. It is obvious to a person skilled in the art that the invention comprises further embodiments within its scope of protection, which is defined by the following claims.