Measuring and testing – Testing of apparatus
Patent
1997-06-24
1998-11-10
Raevis, Robert
Measuring and testing
Testing of apparatus
318626, G05B 1114
Patent
active
058346589
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for monitoring the path of movement of a part which can be moved toward at least one end position by means of a drive, wherein at least one time period is measured which corresponds to a selectable number of revolutions of a drive shaft and the at least one time period is evaluated and supplies a measure for a running behavior of the part.
PRIOR ART
It is known to combine parts with a drive which moves the parts along a path of movement. In this process, the parts can be moved toward at least one end position, in particular, they can be moved back or forth between two end positions. Parts which are movable in such a way are used, for example, in motor vehicles as electrical window lifters or electrically operable sliding roofs. By means of a switching means, the window lifters or the sliding roof can be put into motion via the drive, so that they are moved automatically toward their end position, that is, into their closed position. This involves the risk that a body part of a vehicle occupant gets into the path of movement of an automatically closing window or sliding roof, thus entailing a considerable risk of injury.
It is known to equip parts that are moved in this manner to exhibit a closing force limitation by means of a device, wherein a counterforce exerted on the moved part is determined indirectly and the drive is stopped or reversed as a function of the indirectly determined counterforce. For this purpose, for example, a time period is measured which corresponds to a selectable number of revolutions of a drive shaft of the drive, and if, in the presence of the same number of revolutions of the drive shaft, the time period becomes longer, it is inferred that there is a risk of an object or body part getting caught. Such a procedure is known, for example, from DE 30 34 118 C2.
But the disadvantage of the known methods is that a time measurement takes place only at a moment which is offset in time after the start of the drive in order to take account of a compensation for play of the mechanical parts of the drive. But since during the starting phase, in which the compensation for play takes place, the part, here the window, already traverses a specific amount of its path of movement, which may, for example, amount to several cm, it becomes possible to close the window by means of a clocked operation of the switching means without activating the protection against an object or body part getting caught.
SUMMARY AND ADVANTAGES OF THE INVENTION
In contrast, the method according to the invention offers the advantage that the protection against an object or body part getting caught remains intact over the entire path of movement of the part, even in the presence of a clocked operation of the switching means and therewith a clocked setting into operation of the drive. Immediately after the start of the drive, at least one time period is measured, which corresponds to a selectable number of revolutions of the drive shaft; and this time period is stored temporarily after the drive shaft has gone through a further selectable minimum number of revolutions; and, during a next start of the drive, the time period corresponding to the selectable number of revolutions of the drive shaft is measured again and is compared with the temporarily stored time period; and the drive is stopped or reversed if the temporarily stored time period is exceeded by a selectable measure. Therefore, it is possible in an advantageous manner to realize a monitoring and thus an evaluation of the path of movement of the part immediately when the drive is set into operation. Thus, the startup phase of the drive and the associated compensation for play of the force transmission mechanics exerted on the part to be moved do not have to be considered, because two starting processes that immediately follow one another are compared with one another and thus the startup behavior which is identical in the two starting processes can be masked.
Advantageous embodiments of the invention result from the furthe
REFERENCES:
patent: 5278480 (1994-01-01), Murray
Bosch GmbH
Raevis Robert
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