Patent Description:
Various working lamps, working lights and light installations are known. A common problem with the known working lights relates to glare especially when the working lights are mounted high in comparison to the ground level.

A working light according to the prior art can be found in the document <CIT>.

Optical arrangements according to the prior art are known for example in documents <CIT> and <CIT>.

For example, when a working light is mounted high on top of a working machine or working vehicle, a common problem is that persons walking or standing on the ground level suffer from the glare caused by the working lights on various distances even when the persons remain outside an effective working area of the working lights. This is caused by diffused light distribution. This impacts negatively to general work safety conditions and work ergonomics on various working environments requiring effective working lights such as construction sites and industrial sites and premises, for example.

The glare problem has been presented also in the automotive industry and the automotive field has certain standards and requirements in different countries regarding light distribution and glare of motor vehicles' lightning systems. However, the problem with the working lights is somewhat different than within the automotive industry as in comparison to motor vehicles' lights, the working lights in various conditions and installations are mounted high in relation to ground level or even persons walking or standing on the ground level.

Lightning systems in general may be understood to comprise an optical axis y that is vertical and a horizontal axis x. The standards and industry requirements within the automotive field allow some of the light distribution to extend above the horizontal axis x. For the working lights that are mounted high, the main light beam must remain below the horizontal axis x in order to avoid or to reduct glare.

Therefore, solutions known from the automotive industry can not be applied to the working lights. It becomes apparent that a working light solution that implements glare reduction is also needed.

The object of the present invention is to provide a working light with glare reduction.

Also, the object of the present invention is to provide a working light with glare reduction that may be applied with various working machines and working vehicles and on various industrial sites and conditions.

Further, the object of the present invention is to provide a working light with glare reduction where the light distribution remains below the horizontal axis x with zero tilt angle of the working light when the working light is mounted in high position and the effective working area is located below the horizontal axis x.

Moreover, the object of the present invention is to provide a working light with glare reduction that has high luminating efficiency.

Finally, the object of the present invention is to provide a working light with glare reduction that can be installed without tilting the light.

The objects of the present invention are fulfilled by providing a working light for working machines, the working light comprising at least one light source, an optical vertical axis y and a horizontal axis x wherein the optical axis y and the horizontal axis x intersect each perpendicularly, at least one primary reflector element further comprising a lower edge, a first focus above the horizontal axis x and a second focus below the horizontal axis x, at least one secondary reflector element further comprising a secondary focus, the at least one light source is located on the first focus of the at least one primary reflector element, the at least one secondary reflector element is placed so that its secondary focus is located on the same point with the second focus of the at least one primary reflector element below the horizontal axis x, the at least one primary reflector element is arranged to reflect light beams emitting from the at least one light source via the second focus to the at least one secondary reflector element, characterized in that the lower edge of the at least one primary reflector element is arranged to prevent the light beams emitting from the at least one light source to reach an area above the horizontal axis x, and that at least one secondary reflector element is arranged to form a horizontally spreading light distribution for the light beams so that the most of the light remains below the horizontal axis x.

Some advantageous embodiments of the present invention are disclosed in dependent claims.

The basic idea of the invention is as follows: The working light according to the invention comprises at least one light source. Further, an optical vertical axis y and a horizontal axis x are defined for the working light according to invention. The optical axis y and the horizontal axis x intersect each perpendicularly. The working light according to the invention also comprises at least one primary reflector element, which further comprises a lower edge, a first focus on the optical vertical axis y above the horizontal axis x and a second focus on the optical vertical axis y below the horizontal axis x. Moreover, the working light according to the invention comprises at least one secondary reflector element further comprising a secondary focus.

Advantageously, according to one embodiment of the invention, the at least one light source is located on the first focus of the at least one primary reflector element or light emitting from the at least one light source is directed to the first focus of the at least one primary reflector element by at least one light guide element. Also advantageously, the at least one secondary reflector element is placed so that its secondary focus is located on the same point with the second focus of the at least one primary reflector element on the optical vertical axis y below the horizontal axis x. The effective working area is located below the horizontal axis x and area of the undesired glare is located above the horizontal axis x.

Further, the at least one primary reflector element reflects the light emitting from the at least one light source via the second focus to the at least one secondary reflector element. The lower edge of the at least one primary reflector element is arranged to prevent the light beams emitting from the at least one light source to reach an area above the horizontal axis x. The lower edge of the at least one primary reflector element prevents the direct light beams emitting from the at least one light source to reach an area above the horizontal axis x and the at least one secondary reflector element is arranged to form a light distribution for the light so that the most of the light remains below the horizontal axis x.

Advantageously, the at least one primary reflector element is essentially an ellipsoid or a freeform by its form. If the at least one primary reflector element is essentially a freeform, it should be noted that the focus may be defined as three dimensional space.

The at least one secondary reflector element is arranged to form a light distribution for the received light so that the most of the light remains below the horizontal axis x. The at least one secondary reflector element by its form is at least one of the following: paraboloid, ellipsoid hyperboloid or freeform. However, any other form fit for the purpose may be applied for the at least one secondary reflector element.

According to another advantageous embodiment of the invention, the working light further comprises at least one third reflector element. The at least one third reflector element is essentially an ellipsoid by its form. The at least one third reflector element further comprises a third focus one that is located above the horizontal axis x and a third focus two that is located above the horizontal axis x on the first focus of the at least one primary reflector element. The at least one third reflector element further comprises a third focus one that is located above the horizontal axis x and a third focus two that is located above the horizontal axis x on the first focus of the at least one primary reflector element in case when light emitting from the at least one light source is directed to the first focus of the at least one primary reflector element by the at least one light guide element.

According to a third advantageous embodiment of the invention, the working light may also be implemented by applying any of the previous embodiments vice ver- sa. In that case, the light emitted directly from the at least one light source is directed to the at least one secondary reflector element. In such case, the at least one primary reflector element comprises a first focus on the optical vertical axis y below the horizontal axis x and a second focus on the optical vertical axis y above the horizontal axis x. The lower edge of the at least one primary reflector element is now actually an upper edge. The at least one light source is located on the first focus of the at least one primary reflector element or light emitting from the at least one light source is directed to the first focus of the at least one primary reflector element by at least one light guide element. The at least one secondary reflector element is placed so that its secondary focus is located on the same point with the second focus of the at least one primary reflector element on the optical vertical axis y above the horizontal axis x. Further, the at least one primary reflector element reflects the light emitting from the at least one light source via the second focus to the at least one secondary reflector element. The lower edge of the at least one primary reflector element extends below the horizontal axis x. The lower edge of the at least one primary reflector element prevents the light beams emitting from the at least one light source to reach an area below the horizontal axis x and at least one secondary reflector forms a light distribution for the light beams so that the most of the light beams remain above the horizontal axis x. Namely, the lower edge of the at least one primary reflector element prevents the direct light beams emitting from the at least one light source to reach an area below the horizontal axis x and at least one secondary reflector forms a light distribution for the light beams so that the most of the light beams remain above the horizontal axis x. Further scope of applicability of the present invention will become apparent from the detailed description given hereafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only.

The present invention will become more fully understood from the detailed description given herein below and accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein.

In the following description, considered embodiments are merely exemplary, and one skilled in the art may find other ways to implement the invention. Although the specification may refer to "an", "one; or "some" embodiment(s) in several locations, this does not necessarily mean that each such reference is made to the same embodiment(s), or that the feature only applies to a single embodiment. Single feature of different embodiments may also be combined to provide other embodiments.

<FIG> shows an exemplary schematical representation of the working light according to the invention. The working light according to the invention comprises a frame to which various components and elements of the working light may be installed. The working light according to the invention comprises at least one light source <NUM>, an optical vertical axis y <NUM> and a horizontal axis x <NUM> wherein the optical axis y <NUM> and the horizontal axis x <NUM> intersect each perpendicularly, at least one primary reflector element <NUM> and at least one secondary reflector element <NUM>.

The at least one primary reflector element further comprises a lower edge <NUM>, a first focus <NUM> on the optical vertical axis y <NUM> above the horizontal axis x <NUM> and a second focus <NUM> on the optical vertical axis y <NUM> below the horizontal axis x <NUM>. The at least one secondary reflector element <NUM> further comprises a secondary focus <NUM>. The at least one primary reflector element further comprises an upper edge <NUM>. The first <NUM> and the second focus <NUM> are aligned to the optical vertical axis y <NUM> on a distance from each other. The first <NUM> and the second focus <NUM> are located on a distance from each other on the optical vertical axis y <NUM>.

The at least one light source <NUM> is located on the first focus <NUM> of the at least one primary reflector element <NUM>. Namely, the at least one light source <NUM> is located on the same point with the first focus <NUM> of the at least one primary reflector element <NUM> considering the location of the first focus <NUM> on the optical vertical axis y <NUM> above the horizontal axis x <NUM> The at least one light source <NUM> is aligned to the same point with the first focus <NUM> of the at least one primary reflector element <NUM> considering the location of the first focus <NUM> on the optical vertical axis y <NUM> above the horizontal axis x <NUM>.

The at least one secondary reflector element <NUM> is placed so that its secondary focus <NUM> is located on the same point with the second focus <NUM> of the at least one primary reflector element <NUM> on the optical vertical axis y <NUM> below the horizontal axis x <NUM>. Therefore, the location of secondary focus <NUM> the at least one secondary reflector element <NUM> equals to the location of the second focus <NUM> of the at least one primary reflector element <NUM>.

The at least one primary reflector element <NUM> is arranged to reflect the light emitting from the at least one light source <NUM> via the second focus <NUM> to the at least one secondary reflector element <NUM>. The at least one primary reflector element <NUM> is arranged to reflect light emitting from the at least one light source <NUM> via the first focus <NUM> and the second focus <NUM> to the at least one secondary reflector element <NUM>. Moreover, the at least one primary reflector element <NUM> is arranged to reflect light emitting from the at least one light source <NUM> via the first focus <NUM> and the second focus <NUM> and the secondary focus <NUM> to the at least one secondary reflector element <NUM>.

The lower edge <NUM> of the at least one primary reflector element <NUM> is arranged to prevent the light beams emitting from the at least one light source <NUM> to reach an area above the horizontal axis x <NUM>. Namely, the lower edge <NUM> of the at least one primary reflector element <NUM> is arranged to prevent the direct light beams emitting from the at least one light source <NUM> to reach an area above the horizontal axis x <NUM>. The lower edge <NUM> of the at least one primary reflector element <NUM> may extend below the horizontal axis x <NUM>. The lower edge <NUM> of the at least one primary reflector element <NUM> is arranged to extend below the horizontal axis x <NUM> in order to prevent the direct light beams emitting from the at least one light source <NUM> to reach an area above the horizontal axis x <NUM>. Moreover, the second focus <NUM> of the at least one secondary reflector element <NUM> and the secondary focus <NUM> bundle the light beams emitting from the at least one light source <NUM> to the at least one secondary reflector element <NUM> and the lower edge <NUM> of the at least one primary reflector element <NUM> prevents the direct light beams emitting from the at least one light source <NUM> to reach an area above the horizontal axis x <NUM>. Therefore, all of the light emitting from the at least one light source <NUM> remain below the horizontal axis x <NUM>.

Also advantageously, the at least one secondary reflector element <NUM> is arranged to be at least one of the following: paraboloid, ellipsoid, hyperboloid or freeform. The at least one secondary reflector element <NUM> is arranged to form a light distribution for the light so that the most of the light remains below the horizontal axis x <NUM>. The at least one secondary reflector element <NUM> is arranged to form a light distribution for the light reflected to it by the at least one primary reflector element <NUM> in a manner that the most of the light beam remains below the horizontal axis x <NUM>. The at least one secondary reflector element <NUM> is arranged to form a light distribution for the light reflected to it by the at least one primary reflector element <NUM> in a manner that the most of the light beam remains below the horizontal axis x <NUM> as presented in <FIG> and <FIG>.

<FIG> shows another exemplary schematical representation of the working light according to the invention. The working light according to the invention comprises at least one light source <NUM>, an optical vertical axis y <NUM> and a horizontal axis x <NUM> wherein the optical axis y <NUM> and the horizontal axis x <NUM> intersect each perpendicularly, at least one primary reflector element <NUM> and at least one secondary reflector element <NUM>.

The at least one primary reflector element <NUM> further comprises a lower edge <NUM>, a first focus <NUM> on the optical vertical axis y <NUM> above the horizontal axis x <NUM> and a second focus <NUM> on the optical vertical axis y <NUM> below the horizontal axis x <NUM>. The at least one secondary reflector element <NUM> further comprises a secondary focus <NUM>. The first <NUM> and the second focus <NUM> are located on a distance from each other on the optical vertical axis y <NUM>. The first <NUM> and the second focus <NUM> are aligned to the optical vertical axis y <NUM> on a distance from each other on.

The light emitting from the at least one light source <NUM> is directed to the first focus of the at least one primary reflector element by at least one light guide element <NUM>. The at least one light source <NUM> is located separately from the first focus <NUM> of the at least one primary reflector element <NUM>. The at least one light guide element <NUM> guides the light emitting from the at least one light source <NUM> via first focus <NUM> to the at least one primary reflector element <NUM>.

The at least one primary reflector element <NUM> is arranged to reflect light emitting from the at least one light source <NUM> via the second focus <NUM> to the at least one secondary reflector element <NUM>. The at least one primary reflector element <NUM> is arranged to reflect light emitting from the at least one light source <NUM> via the first focus <NUM> and the second focus <NUM> to the at least one secondary reflector element <NUM>.

The lower edge <NUM> of the at least one primary reflector element <NUM> is arranged to prevent the light beams emitting from the at least one light source <NUM> to reach an area above the horizontal axis x <NUM>. The lower edge <NUM> of the at least one primary reflector element <NUM> is arranged to prevent the direct light beams emitting from the at least one light source <NUM> to reach an area above the horizontal axis x <NUM>. The lower edge <NUM> of the at least one primary reflector element <NUM> may extend below the horizontal axis x <NUM>. The lower edge <NUM> of the at least one primary reflector element <NUM> may extend below the horizontal axis x <NUM> in order to prevent the direct light beams emitting from the at least one light source <NUM> to reach an area above the horizontal axis x <NUM>. The at least one primary reflector element <NUM> may also comprise an upper edge <NUM>.

Moreover, the first focus <NUM> of the at least one first reflector element <NUM> bundles the light emitting from the at least one light source <NUM> via the light guide element <NUM> and then directs the light via the at least one secondary reflector element <NUM> to the second focus <NUM> of the at least one secondary reflector element <NUM> and the secondary focus <NUM>. The second focus <NUM> of the at least one secondary reflector element <NUM> and the secondary focus <NUM> bundle the light beams emitting from the at least one light source <NUM> to the at least one secondary reflector element <NUM> and the lower edge <NUM> of the at least one primary reflector element <NUM> prevents the direct light beams emitting from the at least one light source <NUM> to reach an area above the horizontal axis x <NUM>. Therefore, all of the light emitting from the at least one light source <NUM> remain below the horizontal axis x <NUM>.

Also advantageously, the at least one secondary reflector element <NUM> is arranged to be at least one of the following: paraboloid, ellipsoid, hyperboloid or freeform. The at least one secondary reflector element <NUM> is arranged to form a light distribution for the light so that the most of the light remains below the horizontal axis x <NUM>. The at least one secondary reflector element <NUM> is arranged to form a light distribution for the light reflected to it by the at least one primary reflector element <NUM> in a manner that the most of the light remains below the horizontal axis x <NUM>. The at least one secondary reflector element <NUM> is arranged to form a light distribution for the light reflected to it by the at least one primary reflector element <NUM> in a manner that the most of the light remains below the horizontal axis x <NUM> as presented in <FIG> and <FIG>.

<FIG> and <FIG> present exemplary light distribution formed by a working light according to the invention. The presentations are given within an angle space. <FIG> presents the light distribution projected to the ground level.

It can be seen from the <FIG> that the light distribution is vertically flat (in comparison to vertical axis y <NUM>), spreads horizontally and remains below the horizontal axis x <NUM>. The effective working area is located below the horizontal axis x. The same can be seen from <FIG> whereas the light distribution remains vertically flat and is directed to towards the ground level and spreads horizontally. In case of <FIG> the working light is mounted in the height of two meters, the person facing the light has his/her eyes on in the height of <NUM>,<NUM> meters and the working light has not been tilted (zero tilt angle). Persons outside the effective working area are not affected by the glare.

Claim 1:
A working light for working machines, the working light comprising
- at least one light source (<NUM>, <NUM>)
- an optical vertical axis y (<NUM>, <NUM>) and a horizontal axis x (<NUM>, <NUM>) wherein the optical axis y (<NUM>, <NUM>) and the horizontal axis x (<NUM>, <NUM>) intersect each perpendicularly
- at least one primary reflector element (<NUM>, <NUM>) further comprising a lower edge (<NUM>, <NUM>), a first focus (<NUM>, <NUM>) above the horizontal axis x (<NUM>, <NUM>) and a second focus (<NUM>, <NUM>) below the horizontal axis x (<NUM>, <NUM>)
- at least one secondary reflector element (<NUM>, <NUM>) further comprising a secondary focus (<NUM>, <NUM>), wherein
- the at least one light source (<NUM>, <NUM>) is located on the first focus (<NUM>, <NUM>) of the at least one primary reflector element (<NUM>, <NUM>)
- the at least one secondary reflector element (<NUM>, <NUM>) is placed so that its secondary focus (<NUM>, <NUM>) is located on the same point with the second focus (<NUM>, <NUM>) of the at least one primary reflector element (<NUM>, <NUM>) below the horizontal axis x (<NUM>, <NUM>)
- the at least one primary reflector element (<NUM>, <NUM>) is arranged to reflect light beams emitting from the at least one light source (<NUM>, <NUM>) via the second focus (<NUM>, <NUM>) to the at least one secondary reflector element (<NUM>, <NUM>),
characterized in that
- the lower edge (<NUM>, <NUM>) of the at least one primary reflector element (<NUM>,<NUM>) is arranged to prevent the light beams emitting from the at least one light source (<NUM>, <NUM>) to reach an area above the horizontal axis x (<NUM>, <NUM>), and
- at least one secondary reflector element (<NUM>, <NUM>) is arranged to form a horizontally spreading light distribution for the light beams so that the most of the light beams remain below the horizontal axis x (<NUM>, <NUM>).