Patent Application
20070075480
I. Technical Field
This invention pertains to sheet handling, and particularly to the automated feeding of sheets.
II. Related Art and Other Considerations
Feeders are widely used in the paper handling industry. However, special designs are required for extremely thin, statically charged sheets. Conventional paper feeders on the market cannot reliably separate these pages, as they tend to cling together. As a result, double feeding takes place, making the separation of sheets very important. Manual feeding is the only alternative in these instances.
What is needed, therefore, and an object herein provided, are method, technique, apparatus, for the efficient and effective feeding of sheets, particularly statically-charged thin sheets.
A sheet feeder apparatus and method feeds sheets in a conveyance direction. The apparatus comprises a sheet hopper; a sheet deflector; and a sheet extractor. The sheet hopper is adapted for orienting sheets-to-be-fed in a stack, the sheets of the stack lying essentially parallel to the conveyance direction while lying undeflected in the sheet hopper.
The sheet deflector is arranged for deflecting a top sheet-to-be-fed from the sheet stack from a sheet undeflected acquisition position to a sheet deflected position. The sheet deflector has a major axis oriented essentially parallel to a trailing edge the top sheet-to-be-fed from the sheet stack. The sheet deflector has a port through which suction is selectively applied to the top sheet-to-be-fed.
The sheet deflector is arranged to undergo three degrees of motion. As a first degree of motion, the sheet deflector is arranged for selective rotation about its major axis for moving the top sheet-to-be-fed from the sheet undeflected acquisition position to the sheet deflected position (while, e.g., suction is applied through the port). In so doing, the sheet deflector also experiences its second degree of motion, e.g., selective translation in a plane parallel to the conveyance direction from a nominal position to sheet acquisition position (the sheet acquisition position being closer to the trailing edge of the top sheet-to-be-fed from the sheet stack than the nominal position). As a third degree of motion, the sheet deflector is arranged for selective translation in a direction perpendicular to the conveyance direction for selectively lifting the top sheet-to-be-fed from the sheet stack in the sheet deflected position and selectively resting on the sheet stack.
The sheet extractor is arranged for engaging at least a leading edge of the top sheet-to-be-fed when the top sheet-to-be-fed is in its sheet deflected position and for directing the top sheet-to-be-fed in the conveyance direction.
In an example embodiment, the sheet feeder also comprises a separator for separating the top sheet-to-be-fed when in its sheet deflected position from a remainder of the stack. In one example For example implementation, the separator comprises a source of fluid for blowing fluid between the top sheet-to-be-fed when in its sheet deflected position and the sheet stack for separating the top sheet-to-be-fed from the remainder of the stack.
In an example embodiment, the sheet feeder also comprises a sheet singulator for separating the top sheet-to-be-fed when in its sheet deflected position from another sheet which may be in its sheet deflected position and thereby returning the another sheet to the sheet stack. In an example implementation, the sheet singulator comprises a source of fluid for blowing fluid between the top sheet-to-be-fed when in its sheet deflected position and another sheet which may be in its sheet deflected position and thereby returning the another sheet to the sheet stack.
In an example embodiment, the sheet feeder also comprises a source of compressed gas for applying compressed gas through the port of the sheet deflector to the top sheet-to-be-fed when in its sheet deflected position and when the extractor is engaging the top sheet-to-be-fed.
In an example embodiment, the sheet feeder also comprises a controller for controlling timing of aspects of operation of the sheet feeder. Among the aspects of operation of the sheet feeder supervised or timed by the controller are: (1) the rotation of the sheet deflector; (2) the application of suction though the port of the sheet deflector to the top sheet-to-be-fed; and, (3) the translation of the sheet deflector in the direction perpendicular to the conveyance direction.
In an example embodiment, the sheet deflector comprises a deflector cover, a fluid manifold; and a deflector rod. The port is defined in the deflector cover. The fluid manifold is situated within the deflector cover and in fluid communication with the port. The deflector rod is attached to the deflector cover and collinear with the major axis.
In an example embodiment, the deflector cover is configured with a predetermined profile in a cross section plane perpendicular to the major axis. The predetermined profile has a flat profile segment and a curved profile segment arranged whereby the sheet deflector rolls through at least a portion of its curved profile segment onto the top sheet-to-be-fed to bring the flat profile segment in flush contact with the top sheet-to-be-fed, the flat profile segment of the sheet deflector having the port provided therein.
In an example embodiment, the sheet feeder further comprises a holding arm; a deflector carriage, and an actuator. The holding arm is positioned and arranged for selectively contacting a next sheet-to-be-fed when the sheet extractor engages the top sheet-to-be-fed. The deflector carriage is arranged for carrying the sheet deflector and pivotally connected to the holding arm. The actuator serves for providing relative pivotal movement about a pivot axis of the holding arm and the deflector carriage.
In an example implementation, the deflector carriage comprises a carriage frame; a carriage actuator; and two guide belts. The carriage frame is pivotally connected to the holding arm has had two spaced-apart carriage projections extending therefrom. The carriage actuator has a first end connected to the carriage frame and a piston. The piston is rigidly connected to a bearing. The bearing permits rotation of the sheet deflector about the major axis of the sheet deflector. A first guide belt has a first end connected to a first of the two carriage projections and a second end connected to the bearing. A second guide belt has a first end connected to a second of the two carriage projections and a second end connected to the bearing. The first guide belt and the second guide belt are respectively wrapped in clockwise and counter-clockwise directions about the bearing.
Another aspect of the technology involves a method of operating a sheet feeder for feeding sheets in a conveyance direction. Basic steps involved in an example mode of the method comprises: (1) rotating the sheet deflector about a major axis of the sheet deflector into essentially flush contact with at portion of the trailing edge of the top sheet-to-be-fed from the sheet, thereby translating a sheet deflector from a nominal position to a sheet acquisition position in a plane parallel to a conveyance direction (the sheet acquisition position being closer to a trailing edge of a top sheet-to-be-fed from a sheet stack than the nominal position); (2) applying a vacuum through a port of the sheet deflector to attract the top sheet-to-be-fed to the sheet deflector; (3) rotating the sheet deflector about the major axis of the sheet deflector for moving the top sheet-to-be-fed from a sheet undeflected acquisition position to a sheet deflected position while the vacuum is applied through the port; (4) translating the sheet deflector in a direction perpendicular to the conveyance direction for selectively lifting the top sheet-to-be-fed from the sheet stack; (5) extracting the top sheet-to-be-fed from the sheet deflector in the conveyance direction; and, (6) returning the sheet deflector in the direction perpendicular to the conveyance direction to rest on the sheet stack.
Additional aspects of the method include further comprising separating the top sheet-to-be-fed when in its sheet deflected position from a remainder of the stack; and further comprising separating the top sheet-to-be-fed when in its sheet deflected position from another sheet which may be in its sheet deflected position and thereby returning the another sheet to the sheet stack.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of preferred embodiments as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. All statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.
The sheet deflector 24 is arranged for deflecting a top sheet-to-be-fed, i.e., sheet 32, from the sheet stack 28 from a sheet undeflected acquisition position to a sheet deflected position. The sheet deflector has a major axis (shown by broken line 34) oriented essentially parallel to a trailing edge the top sheet-to-be-fed (sheet 32) from the sheet stack. A trailing edge of sheet 32 is understood with respect to the direction of conveyance depicted by arrow 30. As shown in more detail with reference to
The sheet deflector 24 is arranged for undergoing or experiencing three degrees or types of motion/displacement. As a first degree of motion, the sheet deflector 24 is arranged for selective rotation about its major axis 34 for moving the top sheet-to-be-fed (sheet 32) from the sheet undeflected acquisition position to the sheet deflected position (while, e.g., suction is applied through the port 36). In so doing, the sheet deflector also experiences its second degree of motion, e.g., selective translation in a plane parallel to the conveyance direction 30 from a nominal position to sheet acquisition position (the sheet acquisition position being closer to the trailing edge of the top sheet-to-be-fed from the sheet stack than the nominal position). As a third degree of motion, the sheet deflector 24 is arranged for selective translation in a direction perpendicular to the conveyance direction for selectively lifting the top sheet-to-be-fed (sheet 32) from the sheet stack 28 in the sheet deflected position and selectively resting on the sheet stack 28. These motions will subsequently be described with reference to
The sheet extractor 26 is arranged for engaging at least a leading edge of the top sheet-to-be-fed (sheet 32) when the top sheet-to-be-fed is in its sheet deflected position and for directing the top sheet-to-be-fed in the conveyance direction. In an example embodiment, sheet extractor 26 takes the form of one or more suction belts (e.g., vacuum conveyor belt) and/or other transport mechanism, such as rollers or grippers, for example. As desired, the sheet extractor 26 can be positioned to contact/operate upon either one or both faces of a sheet being extracted. The sheet extractor 26 permanently glides on the upper sheet 32, pulling sheet (sheet 32) to the next processing machine. The sheet 32 actually moves only when it escapes sheet deflector 24.
The sheet feeder 20 also optionally comprises a separator 40 for separating the top sheet-to-be-fed when in its sheet deflected position from a remainder of the stack. In one example For example implementation, the separator comprises a source of fluid exiting through a nozzle or the like (e.g., a small air tube) in the manner depicted by arrow 42 in
The suction applied by sheet deflector 24 may bend not only the leading edge of the top sheet-to-be-fed (e.g., sheet 32), but the second sheet-to-be-fed also (e.g., sheet 32′). To cater to this possibility, the sheet feeder also optionally comprises a sheet singulator 44 for separating the top sheet-to-be-fed when in its sheet deflected position from another sheet which also may be in its sheet deflected position (e.g., sheet 32′) and thereby assisting in the return of the another/second sheet to the sheet stack. In an example implementation, the sheet singulator 44 comprises a source of fluid for blowing fluid in a direction depicted by arrow 46 between the top sheet-to-be-fed (sheet 32) when in its sheet deflected position and another sheet which may be in its sheet deflected position and thereby returning the another sheet to the sheet stack 28. The separation is facilitated by the fact that the bending of the leading edge of the top sheet 32 creates a stress in the second sheet 32′, making easier the separation operation.
In an example embodiment, the sheet feeder 20 also comprises a source 48 of compressed gas for applying compressed gas through the port 36 of the sheet deflector 24 to the top sheet-to-be-fed when in its sheet deflected position and when the extractor is engaging the top sheet-to-be-fed.
In an example embodiment, the sheet feeder 20 also comprises a controller 50 for controlling timing of (e.g., sequencing) aspects of operation of the sheet feeder 20. Among the aspects of operation of the sheet feeder 20 supervised or timed by the controller 50 are: (1) the rotation of the sheet deflector 24; (2) the application of suction though the port 36 of the sheet deflector 24 to the top sheet-to-be-fed (sheet 32); and, (3) the translation of the sheet deflector 24 in the direction perpendicular to the conveyance direction 30. To this end,
The role of controller 50 may be played by a “processor” or “controller”, and as such may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared or distributed. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and may include, without limitation, digital signal processor (DSP) hardware, read only memory (ROM) for storing software, random access memory (RAM), and non-volatile storage.
As shown in
As shown in
Sheet feeder 20 further comprises a holding arm 70; a deflector carriage 72, and an actuator 74. The holding arm 70 is positioned and arranged for selectively contacting a next sheet-to-be-fed when the sheet extractor 26 engages the top sheet-to-be-fed. The deflector carriage 72 is arranged for carrying the sheet deflector 24 and pivotally connected to the holding arm 70. The actuator 74 serves for providing relative pivotal movement about a pivot axis 76 of the holding arm 70 and the deflector carriage 72. Both holding arm 70 and deflector carriage 72 are attached to an unillustrated main frame of sheet feeder 20 at pivot axis 76.
In an example implementation, the deflector carriage 72 comprises a carriage frame 80; a carriage actuator 82; and two guide belts 84, 86. It will be appreciated that the carriage frame 80 structure shown in
The carriage frame 80 of sheet deflector 24, holding arm 70, and sheet extractor 26 control sheet movement alternatively. In order to achieve the right sequence, a “scissor like” mechanism comprised of two arms, e.g., carriage frame 80 of sheet deflector 24 and holding arm 70, pivots around axis 76. These two mechanisms alternatively rest on (and hold) the pile of sheets (8), e.g., stack 28, in sheet hopper 22. The movement of these two mechanisms is controlled by actuator 74, which can be an air cylinder. The carriage frame 80 of sheet deflector 24 holds or carries carriage actuator 82, so that carriage actuator 82 can push/pull sheet deflector 24.
Through the sub-assembly shown in
In one stable position (when actuator 74 is contracted), the paper pile (e.g., stack 28) holds or supports sheet deflector 24 and (through the sub-assembly of
In a second stable position, the holding arm 70 (which serves as a “stopper”) rests on the paper pile (e.g., stack 28) and acting through actuator 74 (when extended) to lift holding arm 70 and carriage frame 80 of sheet deflector 24.
Basic steps involved in an example mode of a method of operating a sheet feeder such as sheet feeder 20 (for feeding sheets in a conveyance direction 30) are illustrated, at least in part, by
As shown in
One reason for sheet deflector 24 to roll on the stack/pile is to have essentially permanent contact with the first sheet (sheet 32), keeping sheet 32 from being pulled by sheet extractor 26 at this point in time. The whole weight of the carriage frame 80 (and through actuator 74 the holding arm 70) rests in this sequence on the pile through sheet deflector 24. Similarly, when actuator 74 is retracted, holding arm 70 rests on the pile raising carriage frame 80 and (through sheet deflector 24) the sheet.
Just after the time shown in
Thus,
The sheet feeder 20 thus “measures” the height of the paper stack 28 as, at times, sheet deflector 24 lies directly on top of stack 28, allowing easy height control of the pile.
In another embodiment, the separation/deflection mechanism is placed under the stack 28 instead of above the stack. In other words, with appropriate alterations and orientation changes, in other embodiments the sheet feeder can function as a bottom feeder rather than a top feeder.
The sheet feeder 20 is particular useful when the next processing machine or station is a laminator or the like. The sheet feeder 20 is also advantageous for use with other types of processing machines or stations.
An advantage of the technology includes low consumption of vacuum. That is, for example, no on-board (loud and expensive) vacuum pump is needed. Rather, the sheet feeder can instead utilize a Bernoulli vacuum generator.
Although various embodiments have been shown and described in detail, the claims are not limited to any particular embodiment or example. None of the above description should be read as implying that any particular element, step, range, or function is essential. The invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements.
This application claims the benefit and priority of U.S. provisional patent application 60/721,990 filed Sep. 30, 2005, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60721990 | Sep 2005 | US |
