Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1994-04-05
1995-06-13
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
250571, 1393701, 356429, D03D 4700, G01N 2184, G01P 1300
Patent
active
054245575
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for optical monitoring of whether a thread or weft is in motion or not in a region illuminated by one or more light sources.
Prior art contact-free signal emitters of the optical type permit substantially only sensing of the presence of and/or slight and/or slow movements of a thread or a weft. In many cases, it is desirable to establish not only whether a thread or weft is located at a given position but moreover whether the thread or the weft is in motion in a determined direction at the desired location. Prior art optical signal emitters do not carry this feature and particularly not so if the thread is extremely thin and/or has a smooth or shiny surface.
SUMMARY OF THE INVENTION
The object forming the basis of the present invention is to satisfy the above-outlined desiderata and, in such instance, in apparatuses of the type disclosed by way of introduction, to obviate or at least reduce to a minimum the drawbacks as outlined above.
This task is solved according to the present invention in an apparatus of the type disclosed by way of introduction in that the region is a part, illuminated by the light source, of a channel with light-reflecting walls, through which the thread or weft extends, that at least one light-sensitive element is placed in said part of the channel in such a manner that their optical axes make an angle with one another, whereby the optical coupling between the light source and the light-sensitive element is influenced by the vibrations occurring in the thread during its movement, for example microvibrations, the changes in the optical coupling being reflected in amplitude variations of a signal from the light-sensitive element. In one plane transversely of the channel, the light source is located in the wall of the channel and is directed towards the longitudinal axis of the channel, while a light-sensitive element is located on either side of the light source in the same plane and is directed towards the longitudinal axis of the channel, the angle between the optical axis of the light source and the optical axis of the light-sensitive elements being such that none impinges on any of the others. The reflecting wall in the channel is arched so that the reflection in the channel will be irregular or chaotic. The light source is placed in an outwardly arched portion of the wall of the channel, which, on both sides thereof, is inwardly arched, that the light-sensitive element is placed at the end of the inwardly arched portion, whereafter the wall is outwardly arched until the outwardly arched portions meet in an inwardly arched portion substantially in register with the light source. A substantially circular translucent wall is disposed in the channel for forming a thread channel, and the space between the said wall and the reflecting wall of the channel is sealed at the ends in order to avoid dirt contamination.
An apparatus according to the present invention makes possible extraordinarily reliable sensing or monitoring of whether a thread or a weft is in motion in a determined direction and this in particular when the thread is extremely thin and has a smooth surface. It has also proved possible to monitor non light-reflective threads and in addition translucent threads.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings.
FIG. 1 is a schematic cross section through a sensing region in one embodiment of an apparatus according to the present invention for illustrating the principle thereof.
FIG. 2 is a side elevation of a prototype of another embodiment of an apparatus according to the present invention.
FIG. 3 shows an end elevation from the right in FIG. 2 of the prototype.
FIG. 4 is a top plan view of the end view in FIG. 3.
FIG. 5 shows a section taken along the line A--A in FIG. 3.
FIG. 6 shows a skeleton coupling diagram for generating a monitoring signal.
FIG. 7 shows a similar section to
REFERENCES:
patent: 4716942 (1988-01-01), Jensen et al.
patent: 4738284 (1988-04-01), Ishikawa et al.
patent: 4852617 (1989-08-01), Hamer et al.
patent: 4963757 (1990-10-01), Lietde et al.
patent: 4994680 (1991-02-01), Brugmann
patent: 5182457 (1993-01-01), Hagmann
patent: 5329961 (1994-07-01), Bouvyn et al.
Lee John R.
Nelms David C.
LandOfFree
Apparatus for monitoring wefts or threads does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for monitoring wefts or threads, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for monitoring wefts or threads will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1311339