Signals and indicators – Indicators – Rotary indicator with actuating means
Reexamination Certificate
1999-06-19
2001-01-30
Hirshfeld, Andrew H. (Department: 2859)
Signals and indicators
Indicators
Rotary indicator with actuating means
C116S288000, C116S301000, C362S030000
Reexamination Certificate
active
06178917
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The invention relates to a pointer instrument, especially one for a motor vehicle, having two pointers which can each be deflected by a pointer drive and each have a pointer flag, it being possible for the pointers to pivot independently of each other about a common axis of rotation.
In modern motor vehicles, a large number of items of information are signaled to the driver by pointer instruments. Whereas earlier one was satisfied with just a speed indicator, pointer instruments are also increasingly provided nowadays for the engine speed, the fuel level or the temperature. For traffic safety reasons, these instruments must be arranged in the continuous field of view of the driver as a result of which the installation space which is available is often severely restricted.
It has therefore already been proposed to integrate two independent, coaxial pointers into one pointer instrument, similar to a clock, in order in this way to make optimum use of the available space. However, the disadvantage here is that, depending on the position of the pointer flags, the lower pointer flag is hidden by the upper pointer flag and therefore cannot be read directly by the driver. As a result, in the event of a fleeting glance at the pointer instrument, confusion in the allocation of the pointer flag may occur. Furthermore, the above-described design requires multiple scaling, so that increased attention is required of the driver for the purpose of reading. The inherent advantage of pointer instruments over digital indicators, that changes in the indicated value can be registered without the indicator having to be read exactly for this, is therefore no longer provided in the case of two coaxial pointer flags. Furthermore, the relatively great distance of the upper pointer from the dial has a detrimental effect so that reading inaccuracies occur, depending on the viewing angle, and the pointer instrument has a large overall height. In practice, the abovementioned disadvantages have led to pointer instruments with a plurality of pointer flags not being able to become widespread, with the exception of pointer instruments for the time of day.
SUMMARY OF THE INVENTION
The invention is based on the problem of configuring a pointer instrument with two pointer flags, wherein each pointer flag has a reading accuracy that essentially unchanged as compared with conventional pointer instruments equipped with only one pointer flag. At the same time, the intention is, in particular, to eliminate erroneous allocations of the pointer flag to the associated scale.
According to the invention, this problem is solved by the pointer flags being essentially arranged in a common plane and in each case so that they can pivot in a region which is formed by a sector of a circle whose center is arranged on the axis of rotation. The arrangement of the pointer flags in one plane permits, on the one hand, quick and fault-free assignment of the pointer position to the associated scale and, on the other hand, at the same time a space-saving low design. The pointer flags can each pivot in a separate sector of a circle, so that overlapping of the pointer flags is ruled out. In principle, the number of pointer flags designed in this way is any desired, the recommendation in practice being up to a maximum of four pointer flags, for reasons of clarity.
The common axis of rotation, about which the pointer flags are arranged so that they can pivot, can be aligned essentially perpendicular to the plane of a dial and permanently connected to the instrument housing. However, one embodiment of the invention, in which the common axis is designed as a pointer shaft of one of the pointer flags, is particularly advantageous. The other or the further pointer flags are in this case arranged in relation to the pointer shaft so that they can pivot around the latter. This achieves a compact design which at the same time also offers the possibility of supplementing existing pointer instruments with additional pointers. In this case, the pointer flags are arranged so that they can pivot independently of one another.
A particularly advantageous embodiment of the invention is also provided when the pointer flags can be deflected by means of a form-fitting mechanism. This permits exact and fault-free transmission of the position of the respective pointer drive system to the pointer shaft and, respectively, to the pointer flag. In this case, in particular, displacements of the zero point on account of slip are ruled out.
Particularly beneficial for this purpose is a development of the invention in which the mechanism is a gear mechanism. This permits reliable deflection of the pointer flag to be achieved using simple means, it being possible for any step-up or step-down ratios to be achieved between the gear wheels of the gear mechanism. In this case, the gearwheels may also be designed, for example, in the form of sectors of a circle with an opening angle needed to deflect the pointer flag.
It is also advantageous if the mechanism is equipped with gearwheels that are prestressed toward one other. This prestress allows play, which interferes with the reading accuracy, to be avoided. As a result, in particular any reversal of the direction of rotation can be detected more quickly and is displayed in a fault-free manner.
Another, Particularly advantageous form of the development of the invention is also provided if the mechanism is a toothed-belt mechanism. This permits the implementation of a design which is simultaneously space-saving and compact. At the same time, the transmission of force takes place without play, so that it is possible to dispense with an additional tensioning means.
Another, particularly advantageous embodiment of the invention is provided by the pointer flags being designed to be transparent in at least one sub-area. This permits the reading accuracy to be improved significantly, since even regions of the dial which are completely or partially hidden by the pointer flag can be read.
The pointer flags are preferably designed to conduct light and to couple light out in at least one sub-area, as a result of which the illumination of the pointer flags, which considerably improves the readability of the pointer instrument, in particular when the surroundings are dark, is made possible. In this case, a particularly beneficial embodiment may be achieved by the pointer flags each being designed to be illuminated by means of a light-injection element. As a result, the respectively illuminated pointer flag stands out clearly visibly against the dial. In this case, it is easily possible to illuminate the different pointer flags with different colors, so.that confusion is ruled out by the color contrast. Also conceivable are embodiments in which the illumination of the pointer flags is variable in terms of lightness or color, depending on the deflection angle, and thus, for example, a deviation from a desired value can be detected immediately.
One could imagine designing the light-injection element as a disk arranged concentrically with the axis of rotation. However, the element is particularly light—and hence the torque to be applied by the pointer drive is comparatively low—and the light losses in the light-injection element is low if, according to another advantageous development of the invention, the light-injection element has a cross section in the form of an annular segment, the center of the annular segment being arranged approximately on the axis of rotation.
The light to be radiated into the pointer by a light source is utilized to a particularly high extent if a source radiating light into the light-injection element is arranged opposite the light-injection element on a circuit board belonging to the pointer instrument. In this way, the pointer instrument also has a very compact construction.
Another particularly favorable embodiment is provided by the pointer flags each having a light source radiating in directly. By this means, a light-injection point, needed in each case for a pointer fla
Farber Martin A.
Hirshfeld Andrew H.
Mannesmann VDO AG
LandOfFree
Pointer instrument does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pointer instrument, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pointer instrument will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2503555