Sheet feeding or delivering – Feeding – With means to interrupt feeding
Patent
1992-07-21
1994-04-19
Skaggs, H. Grant
Sheet feeding or delivering
Feeding
With means to interrupt feeding
271262, B65H 712
Patent
active
053039122
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a device for detecting double sheets in an apparatus for separating a sheet film from a sheet-film stack, preferably a stack contained in a supply magazine, with a suction device which for releasing the film to be removed bends the front area of the film, which is engaged by the suction device, with respect to the sheet-film plane.
In a device of this type which is known from DE-OS 37 05 851, a sheet-film loaded in a supply magazine is engaged in its front section by suction elements and separated from the underlying sheet-film stack in that the suction elements are tilted. Subsequently the sheet film is removed from the supply magazine by the pivotally guided suction elements and moved through a light barrier which is arranged in its path of movement and detects whether or not more than one sheet film was attracted. If the light barrier detects that there is more than one sheet film the removal operation is interrupted by a control device, the direction of pivotal movement of the suction elements is reversed and the sheet films are returned to, and deposited in the supply magazine. By completely repeating the removal operation several removal attempts are made in order to release the second sheet film adhering to the first by repeatedly tilting the suction elements. During the repeated removal attempts by which the sheet film is to be released in this known device the sheet film is affected in an undesired manner by the relative movement between the sheet film to be removed and the supply stack as well as by the friction occurring at the guide means.
It is the object of the invention to provide a device of the generic type such that double sheet films are detected without the film being damaged.
In accordance with the invention this object is attained in that a thickness sensor is moved into the bent-off area of the sheet film while said film is still located on the sheet-film stack.
According to an advantageous modification of the invention the thickness sensor consists of a first lever which can be pivoted jointly with the suction device and on which a second lever is pivotally mounted which actuates a switch, rollers sensing the upper and the lower face respectively of the sheet film being rotatably mounted on said levers.
Advantageously pivotal movement of the levers of the thickness sensor is limited to a range between a sensing position and an initial position, with the initial position being defined by an abutment which can be electromagnetically operated and which releases the thickness sensor to assume its sensing position.
Preferably the thickness sensor is returned to its initial position in that it is positively engaged, and taken along by the suction device.
Thanks to the design and arrangement of the thickness sensor in accordance with the invention, it is detected even prior to the removal of a sheet film from the sheet-film stack whether a second sheet film adheres to the first sheet film so that the sheet film is initially not withdrawn from the sheet film stack in such a case. Only when the thickness sensor has detected that a single sheet film has been properly engaged is the actual film removal operation initiated so that the sheet film is only transported when it has been separated in a functionally correct manner and in this way is protected from damage.
Further features and advantages can be inferred from an embodiment of the invention illustrated in the drawing and from the subclaims. The drawing shows schematically in
FIG. 1 a lateral view of the device in its initial position;
FIG. 2 a view of the device according to FIG. 1 in its sensing position, and
FIG. 3 an oblique view of details of the device according to FIG. 1.
The invention is described in connection with a device for removing sheet films 3a from a sheet-film supply magazine 1, said device having a suction plate 21 with a plurality of suction elements 6.
Such a device is known for example from an apparatus for loading sheet film into a sheet-film magazine which has been disclosed in DE 37 05 851
REFERENCES:
patent: 3744787 (1973-07-01), Morrison
patent: 3885780 (1975-05-01), Morrison
patent: 3993303 (1976-11-01), Riedl et al.
patent: 4462585 (1984-07-01), Gieson et al.
patent: 4506876 (1985-03-01), Nishibori
patent: 4531726 (1985-07-01), Bornstein
patent: 4533133 (1985-08-01), Hams
patent: 4697246 (1987-09-01), Zemke et al.
patent: 4763890 (1988-08-01), Zimmerman et al.
Blank Kurt
Ueffinger Friedrich
Druzbick Carol Lynn
Eastman Kodak Company
Schmidt Dana M.
Skaggs H. Grant
LandOfFree
Device for detecting double sheet films does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for detecting double sheet films, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for detecting double sheet films will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-15548