Title:
Pneumatic sheet transport and alignment mechanism
United States Patent 3918706
Abstract:
A pneumatic sheet transport and alignment mechanism is disclosed utilizing the orientation of the air jets in the pneumatic transport to cause the sheet being transported to be moved laterally to engage an edge guide such that the sheet is properly aligned for subsequent operations upon exiting from the transport and alignment mechanism. Additionally a technique is disclosed which allows the sheet to be progressively engaged with the edge guide or reference edge such that the trailing corner of the sheet as it progresses through the transport is engaged with the reference edge prior to the leading corner thereby avoiding jams and retarded sheets.
US Patent References:
Sheet feeding and registering device
Spiess - April 1941 - 2240424
Pneumatically operated document sensing station
Khorry et al. - September 1963 - 3103850
/3588096.html
Leiter - June 1971 - 3588096
SHEET-CONVEYING DEVICE
Schwebel - November 1971 - 3624807
PNEUMATIC TRANSPORT TRACK
Groeber - July 1973 - 3747922
Sheet feeding and registering device
Spiess - April 1941 - 2240424
Pneumatically operated document sensing station
Khorry et al. - September 1963 - 3103850
/3588096.html
Leiter - June 1971 - 3588096
SHEET-CONVEYING DEVICE
Schwebel - November 1971 - 3624807
PNEUMATIC TRANSPORT TRACK
Groeber - July 1973 - 3747922
Application Number:
05/482310
Publication Date:
11/11/1975
Filing Date:
06/24/1974
View Patent Images:
Export Citation:
Assignee:
International Business Machines Corporation (Armonk, NY)
Primary Class:
Other Classes:
4/541.600, 406/87, 271/195
International Classes:
B65H5/22; B65H9/00; B65H9/04; B65H5/22
Field of Search:
271/248,250,251,195,97 226/97 302/31
Primary Examiner:
Blunk, Evon C.
Assistant Examiner:
Stoner Jr., Bruce H.
Attorney, Agent or Firm:
Letson, Laurence R.
Claims:
I claim
1. A pneumatic sheet transporting and aligning device comprising a transport plane defined by restraining means positioned on two sides of said plane and an edge guide aligning means;
2. A pneumatic transport and aligner for transporting sheet material and aligning said sheet with an edge alignment guide comprising:
3. The transport and alignment device of claim 2 wherein said groups of nozzles are positioned and angularly placed with respect to a sheet of said material that in addition to said translating vector and said transporting vector, at least one of said groups of said nozzles is angularly oriented with respect to others of said nozzles and said edge guide, that the cooperative forces of the air flow from said nozzles creates a turning movement about an axis perpendicular to the plane of said sheet.
4. The transport and alignment device of claim 2 wherein the vectors of forces created by the orientation of said nozzles coact on said sheet to rotate said sheet to cause the trailing corner of the aligner engageable edge of said sheet to engage said edge aligner guide prior to the engagement of said edge of said sheet.
1. A pneumatic sheet transporting and aligning device comprising a transport plane defined by restraining means positioned on two sides of said plane and an edge guide aligning means;
2. A pneumatic transport and aligner for transporting sheet material and aligning said sheet with an edge alignment guide comprising:
3. The transport and alignment device of claim 2 wherein said groups of nozzles are positioned and angularly placed with respect to a sheet of said material that in addition to said translating vector and said transporting vector, at least one of said groups of said nozzles is angularly oriented with respect to others of said nozzles and said edge guide, that the cooperative forces of the air flow from said nozzles creates a turning movement about an axis perpendicular to the plane of said sheet.
4. The transport and alignment device of claim 2 wherein the vectors of forces created by the orientation of said nozzles coact on said sheet to rotate said sheet to cause the trailing corner of the aligner engageable edge of said sheet to engage said edge aligner guide prior to the engagement of said edge of said sheet.
Description:
BACKGROUND OF THE INVENTION
It is desirable in many circumstances to align a sheet such as a sheet of paper after it has departed from one process and before being reprocessed or further handled. An example of this is in the printing and photocopying environments. An example of a need to align a sheet in a different but generally parallel feed path, is where the copy or sheet exiting from a photocopying machine or printing press is exited in a path which is not properly aligned with a sheet receiving and processing mechanism such as a sheet sorter or collator. This situation occurs where it is desired that the sheets be presented to the operator of the device at the front of the sheet collating or sorting machine while at the same time accommodating that requirement with the fact that the sheets may exit from the device which produces the copies at a location closer to the back of the machine.
In such situations, it is necessary to attempt to align the sheet toward the front of the apparatus prior to further processing and thereby cause the sheets to be collated or sorted and deposited in bins for the operator to remove from the front of the machine.
It is further desirable to provide a device which is either continuously on or off as desired by the machine operator which is exceedingly simple in operation both from a maintenance and operational reliability standpoint.
Pressurized pneumatic conveyors have shown a propensity for reliability and simplicity when handling sheets and strips of materials.
Pneumatic guides and transports for strips, have been previously disclosed in U.S. Pat. No. 3,103,850 and U.S. Pat. No. 3,705,413. In both of these prior art applications, air jets having a direction of air flow in a plane parallel to the direction of movement desired of the strip being transported are disclosed, however, there is no alignment function with the exception of a complete restraining movement against lateral movement provided by the rigid mechanical members of the apparatus. The use of angularly oriented jets or nozzles to provide a lubricated air bearing transport and moving force is well illustrated in these devices. In both of these devices, the material being transported is of a strip nature rather than a sheet nature and therefore is sufficiently long that it provides its own guiding forces in cooperation with the rigid side members of the transport mechanism.
Other devices have been disclosed which utilize an air cushion on one side of the card or sheet being transported in cooperation with angularly oriented propulsion jets to provide the forward vector of force, which are oriented generally such that the projection of their axis onto the plane of transport is parallel to the direction desired in transporting the sheet. An example of this device is U.S. Pat. No. 3,405,977. This device also provides a rigid physical retaining member along the sides of the transport path such that the sheet is physically restrained laterally during transport.
An additional device disclosing the use of propulsion jets to move sheets is U.S. Pat. No. 3,198,515 which discloses the use of propulsion jets on one side of a sheet in one direction and the propulsion jets in an opposite direction on the opposite side such as to separate two sheets in the event that two sheets are attempted to be fed at the same time.
In this device, the only alignment forces are exerted by the rigid base member disclosed in the drawings together with the action of gravity on the sheet being fed. INVENTION U.S. Pat. No. 3,614,168 discloses a conveyor system using the Bernoulli phenomena together with atmospheric pressure acting on the backside of the sheet being transported. Selection of the path may be made from several possible paths by the activation of a control unit which controls the pressurization of one of several plenums thus providing the Bernoulli low pressure attracting region for that path and providing no forces for the other path. The system provides physical side restraints with no alignment function being disclosed.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to align a sheet for further operations during the transporting of the sheet, using a pneumatic transporting and alignment techniques.
It is another object of the invention to prevent jamming of the sheet within the transport mechanism during transportation and alignment.
It is still another object of the invention to improve and simplify sheet transportation and alignment apparatuses.
The foregoing objects are accomplished by the formation of a transport path or transport region between two restraining means and the angularly forwardly impinging of air from nozzles or jets onto the sheet being transported to provide the sheet with both a transporting forward force or vector and a lateral force or vector to accomplish alignment and positioning. Additionally the jets are broken into groups to provide a simultaneous twisting or turning moment on the sheet to prevent the leading corner from engaging the edge guide or reference guide early thus preventing the jamming of a sheet into the edge guide which would prevent continued operation of the apparatus.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.
In the Drawings
FIG. 1 is a plan view of the bottom restraining means and air jets oriented to accomplish the objects of the invention.
FIG. 2 is a sectional view of the top and bottom restraining means together with the nozzles and jets.
FIG. 3 illustrates an alternative embodiment of the arrangement in FIG. 2.
DETAILED DESCRIPTION
Referring to FIG. 1, a top and bottom restraining means 12, 10 is provided to support the sheet and to guide the sheet with respect to one plane during its transport through the transport and alignment apparatus. These restraining means 10 may be of many different configurations but may most conveniently be formed of a relatively thin sheet of material such as aluminum or other metal sheeting to provide a generally flat surface. It should be recognized that should there be a need for making the surface other than flat, it may have small surface irregularities such as shallow bend but that the apparatus functions best with a flat surface.
A complimentary top restraining means 12, illustrated in FIGS. 1, 2 and 3, is placed over and maintained spaced apart from the bottom restraining means 10 thereby providing a relatively thin channel or spacing between the two restraining means 10, 12 for the sheet to be restrained within and acted upon by the air flow from the transport and aligning nozzles. For reference purposes and for alignment a reference edge or edge guide 14 is provided along one edge of bottom restraining means 10, and extending across the gap between restraining plates 10, 12.
Where bottom restraining means 10 or bottom plate 10 is in fact a solid metal plate the pneumatic nozzles or air jets 18, 22, 34 used for transporting and aligning may be either formed by drilling through the plate at the desired angle or may be formed by creating an opening 42 in the plate 10, 12 and then projecting a nozzle or tube through that opening at the appropriate desired angle. In either event, the techniques are equivalent and provide substantially identical results.
Depending upon the size of the sheets to be accommodated by the transport mechanism, a plurality of jets are positioned and aimed through bottom restraining means 10 and top restraining means 12. It is desirable to have a plurality of jets acting upon a sheet at any one time with the minimum number being two and the maximum number being determined by nozzle size and spacing.
Recognizing that the precise number of jets acting on a sheet at any one time is not a critical element of this invention, the device is illustrated in FIG. 1 with a total of nine jets in the bottom restraining means 10 and a like number would be found in the top restraining means 12 illustrated in sectional view in FIG. 2. The transport and aligning mechanism is positioned such that a sheet may be received from a device, such as, for example a printer of any of several diverse types, i.e., offset printer, photographic printer or electrophotographic printer or electrostatic copying apparatus, or other sheet outputting device.
Generally the sheet is outputted from whatever base machine is involved by means of conventional sheet handling techniques such as belts, pinch rolls, or other well known sheet transport mechanisms. With a knowledge of the size sheets that the apparatus outputting the sheet material will accommodate, the transport and aligner may be adapted to accommodate sheets of that size, or may be made to accommodate sheets of a plurality of sizes.
A better understanding of the operation and construction of the invention may be secured from the following of the examples as shown in FIGS. 1 and 2 with the modification in FIG. 3.
Referring to FIG. 1, jets 16, 18, 20 and 22 are all oriented at an angle sufficient to impart a substantial translating or lateral force vector to the sheet 8. As can be seen, the sheet 8 is still engaged by pinch rolls 40 of the base machine or printer and thus the effect of jets 16 and 18 have not overcome the feed effects of pinch rolls 40. As the sheet progresses or pinch rolls 40 become disengaged the forces exerted by jets 16 and 18 begin to translate sheet 8 in the direction of arrows 24. As sheet 8 progresses in the direction of arrows 24, the sheet is engaged by the air flow from jets 20 and 22 which provide additional force in the direction of arrows 24. At about the same time as the sheet is being engaged by jets 20 and 22, the lower edge in FIG. 1 of sheet 8 is being acted upon by the flow from jet 26. As jet 26 acts on the sheet a larger component of force is exerted in the forward or transport direction, i.e., from right to left in FIG. 1, and a diminished translating vector, i.e., from top to bottom, is placed on the lower end of sheet 8. In view of the increase forward force of jet 26 there is created a turning moment about an axis which is perpendicular to sheet 8 causing the sheet to have a tendency to turn in a clockwise direction. As the sheet progresses along the general direction of arrows 24, the sheet will engage the air flow from jet 28 which further reinforces the action of jet 26.
While jets 16, 18, 20 and 22 are generally oriented the same providing a large translational vector and a substantial transporting vector, these jets may be considered as one group providing primarily an aligning and transporting force. Jets 26 and 28 having a reduced angular orientation with respect to the reference edge 14 provide primarily a turning and transporting force. The turning force tends to engage the trailing corner of sheet 8, designated as 9, with reference edge 14 prior to the leading corner designated 7 thereby preventing corner 7 from abutting into reference edge 14 and crumpling or otherwise causing a jam in the transport apparatus. With the trailing corner 9 in contact with the reference edge 14, the turning moment created by jets 26 and 28 will be offset or overcome and the forces of jets 16, 18, 20 and 22 together with the translational vectors of jets 26 and 28 will act with respect to corner 9 causing the sheet to translate leftward and at the same time then rotate in a counterclockwise direction placing the edge defined by corners 7 and 9 of sheet 8 against the reference edge for accurate positioning. When the force of the sheet 8 against reference edge 14 is sufficient to overcome the translational effects of those jets still acting on it, the forward vector will translate the sheet until jets 30, 32 and 34 engage it. As can be seen from FIG. 1, the angular orientation of jets 30, 32 and 34 is still such that they form a small acute angle with respect to the reference edge but such that the translational force vectors created thereby are small with respect to the forward transporting vector. Thus a force is exerted on sheet 8 to keep the edge thereof abutted against edge aligner 14 or reference edge 14 and at the same time provide a substantial forward moving force to transport the paper out of the transporter and aligner apparatus. After the paper 8 leaves the transport mechanism and is aligned against the reference edge 14, the sheet may be transported to any other utilizing device as for example a collator or sorter.
FIG. 3 more clearly illustrates the use of tube type jets 44 extending through openings 42 in the top and bottom restraining means 10 and 12. The tubes are angled to form converging air flows and provide, in the transport region between restraining means 10 and 12, a low pressure or Bernoulli effect which will have the effect of towing the paper in the air flow and not on the restraining means 10 or 12. The configuration shown in FIG. 3 illustrates the use of jets protruding through openings and these jets are supplied from an accumulator or plenum 50 which is in turn supplied with pressurized air from a pump 52.
FIG. 2 illustrates an alternative embodiment wherein the upper and lower restraining means have been formed as part of a plenum chamber 54 which is pressurized by pump 52. The jets are then formed by holes being drilled at the appropriate angular orientation both with respect to the paper path and also slanted in the direction of travel desired by the paper at any one point to cause converging Bernoulli air flows to urge the paper forward.
Particular advantages of this type of system over mechanical systems is that the paper is free to overcome the forces of the jets when it engages a rigid alignment member such as the reference edge and not crumple, tear or otherwise mutilate the paper where a mechanical device is in firm physical contact with the page may create tears, wrinkles, or crumpling of the sheet, and resulting paper jams.
An additional reason for utilizing this mechanism over a mechanical device would be its relatively inexpensive construction inasmuch as there are very few moving mechanical parts, primarily confined to the pressure pump. Additionally the positive air flow through jets does not require an air filtering system such as vacuum transports, the type of mechanism which can become contaminated by the entraining of contaminate particles such as dirt or paper dust in the air flow.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.
It is desirable in many circumstances to align a sheet such as a sheet of paper after it has departed from one process and before being reprocessed or further handled. An example of this is in the printing and photocopying environments. An example of a need to align a sheet in a different but generally parallel feed path, is where the copy or sheet exiting from a photocopying machine or printing press is exited in a path which is not properly aligned with a sheet receiving and processing mechanism such as a sheet sorter or collator. This situation occurs where it is desired that the sheets be presented to the operator of the device at the front of the sheet collating or sorting machine while at the same time accommodating that requirement with the fact that the sheets may exit from the device which produces the copies at a location closer to the back of the machine.
In such situations, it is necessary to attempt to align the sheet toward the front of the apparatus prior to further processing and thereby cause the sheets to be collated or sorted and deposited in bins for the operator to remove from the front of the machine.
It is further desirable to provide a device which is either continuously on or off as desired by the machine operator which is exceedingly simple in operation both from a maintenance and operational reliability standpoint.
Pressurized pneumatic conveyors have shown a propensity for reliability and simplicity when handling sheets and strips of materials.
Pneumatic guides and transports for strips, have been previously disclosed in U.S. Pat. No. 3,103,850 and U.S. Pat. No. 3,705,413. In both of these prior art applications, air jets having a direction of air flow in a plane parallel to the direction of movement desired of the strip being transported are disclosed, however, there is no alignment function with the exception of a complete restraining movement against lateral movement provided by the rigid mechanical members of the apparatus. The use of angularly oriented jets or nozzles to provide a lubricated air bearing transport and moving force is well illustrated in these devices. In both of these devices, the material being transported is of a strip nature rather than a sheet nature and therefore is sufficiently long that it provides its own guiding forces in cooperation with the rigid side members of the transport mechanism.
Other devices have been disclosed which utilize an air cushion on one side of the card or sheet being transported in cooperation with angularly oriented propulsion jets to provide the forward vector of force, which are oriented generally such that the projection of their axis onto the plane of transport is parallel to the direction desired in transporting the sheet. An example of this device is U.S. Pat. No. 3,405,977. This device also provides a rigid physical retaining member along the sides of the transport path such that the sheet is physically restrained laterally during transport.
An additional device disclosing the use of propulsion jets to move sheets is U.S. Pat. No. 3,198,515 which discloses the use of propulsion jets on one side of a sheet in one direction and the propulsion jets in an opposite direction on the opposite side such as to separate two sheets in the event that two sheets are attempted to be fed at the same time.
In this device, the only alignment forces are exerted by the rigid base member disclosed in the drawings together with the action of gravity on the sheet being fed. INVENTION U.S. Pat. No. 3,614,168 discloses a conveyor system using the Bernoulli phenomena together with atmospheric pressure acting on the backside of the sheet being transported. Selection of the path may be made from several possible paths by the activation of a control unit which controls the pressurization of one of several plenums thus providing the Bernoulli low pressure attracting region for that path and providing no forces for the other path. The system provides physical side restraints with no alignment function being disclosed.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to align a sheet for further operations during the transporting of the sheet, using a pneumatic transporting and alignment techniques.
It is another object of the invention to prevent jamming of the sheet within the transport mechanism during transportation and alignment.
It is still another object of the invention to improve and simplify sheet transportation and alignment apparatuses.
The foregoing objects are accomplished by the formation of a transport path or transport region between two restraining means and the angularly forwardly impinging of air from nozzles or jets onto the sheet being transported to provide the sheet with both a transporting forward force or vector and a lateral force or vector to accomplish alignment and positioning. Additionally the jets are broken into groups to provide a simultaneous twisting or turning moment on the sheet to prevent the leading corner from engaging the edge guide or reference guide early thus preventing the jamming of a sheet into the edge guide which would prevent continued operation of the apparatus.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.
In the Drawings
FIG. 1 is a plan view of the bottom restraining means and air jets oriented to accomplish the objects of the invention.
FIG. 2 is a sectional view of the top and bottom restraining means together with the nozzles and jets.
FIG. 3 illustrates an alternative embodiment of the arrangement in FIG. 2.
DETAILED DESCRIPTION
Referring to FIG. 1, a top and bottom restraining means 12, 10 is provided to support the sheet and to guide the sheet with respect to one plane during its transport through the transport and alignment apparatus. These restraining means 10 may be of many different configurations but may most conveniently be formed of a relatively thin sheet of material such as aluminum or other metal sheeting to provide a generally flat surface. It should be recognized that should there be a need for making the surface other than flat, it may have small surface irregularities such as shallow bend but that the apparatus functions best with a flat surface.
A complimentary top restraining means 12, illustrated in FIGS. 1, 2 and 3, is placed over and maintained spaced apart from the bottom restraining means 10 thereby providing a relatively thin channel or spacing between the two restraining means 10, 12 for the sheet to be restrained within and acted upon by the air flow from the transport and aligning nozzles. For reference purposes and for alignment a reference edge or edge guide 14 is provided along one edge of bottom restraining means 10, and extending across the gap between restraining plates 10, 12.
Where bottom restraining means 10 or bottom plate 10 is in fact a solid metal plate the pneumatic nozzles or air jets 18, 22, 34 used for transporting and aligning may be either formed by drilling through the plate at the desired angle or may be formed by creating an opening 42 in the plate 10, 12 and then projecting a nozzle or tube through that opening at the appropriate desired angle. In either event, the techniques are equivalent and provide substantially identical results.
Depending upon the size of the sheets to be accommodated by the transport mechanism, a plurality of jets are positioned and aimed through bottom restraining means 10 and top restraining means 12. It is desirable to have a plurality of jets acting upon a sheet at any one time with the minimum number being two and the maximum number being determined by nozzle size and spacing.
Recognizing that the precise number of jets acting on a sheet at any one time is not a critical element of this invention, the device is illustrated in FIG. 1 with a total of nine jets in the bottom restraining means 10 and a like number would be found in the top restraining means 12 illustrated in sectional view in FIG. 2. The transport and aligning mechanism is positioned such that a sheet may be received from a device, such as, for example a printer of any of several diverse types, i.e., offset printer, photographic printer or electrophotographic printer or electrostatic copying apparatus, or other sheet outputting device.
Generally the sheet is outputted from whatever base machine is involved by means of conventional sheet handling techniques such as belts, pinch rolls, or other well known sheet transport mechanisms. With a knowledge of the size sheets that the apparatus outputting the sheet material will accommodate, the transport and aligner may be adapted to accommodate sheets of that size, or may be made to accommodate sheets of a plurality of sizes.
A better understanding of the operation and construction of the invention may be secured from the following of the examples as shown in FIGS. 1 and 2 with the modification in FIG. 3.
Referring to FIG. 1, jets 16, 18, 20 and 22 are all oriented at an angle sufficient to impart a substantial translating or lateral force vector to the sheet 8. As can be seen, the sheet 8 is still engaged by pinch rolls 40 of the base machine or printer and thus the effect of jets 16 and 18 have not overcome the feed effects of pinch rolls 40. As the sheet progresses or pinch rolls 40 become disengaged the forces exerted by jets 16 and 18 begin to translate sheet 8 in the direction of arrows 24. As sheet 8 progresses in the direction of arrows 24, the sheet is engaged by the air flow from jets 20 and 22 which provide additional force in the direction of arrows 24. At about the same time as the sheet is being engaged by jets 20 and 22, the lower edge in FIG. 1 of sheet 8 is being acted upon by the flow from jet 26. As jet 26 acts on the sheet a larger component of force is exerted in the forward or transport direction, i.e., from right to left in FIG. 1, and a diminished translating vector, i.e., from top to bottom, is placed on the lower end of sheet 8. In view of the increase forward force of jet 26 there is created a turning moment about an axis which is perpendicular to sheet 8 causing the sheet to have a tendency to turn in a clockwise direction. As the sheet progresses along the general direction of arrows 24, the sheet will engage the air flow from jet 28 which further reinforces the action of jet 26.
While jets 16, 18, 20 and 22 are generally oriented the same providing a large translational vector and a substantial transporting vector, these jets may be considered as one group providing primarily an aligning and transporting force. Jets 26 and 28 having a reduced angular orientation with respect to the reference edge 14 provide primarily a turning and transporting force. The turning force tends to engage the trailing corner of sheet 8, designated as 9, with reference edge 14 prior to the leading corner designated 7 thereby preventing corner 7 from abutting into reference edge 14 and crumpling or otherwise causing a jam in the transport apparatus. With the trailing corner 9 in contact with the reference edge 14, the turning moment created by jets 26 and 28 will be offset or overcome and the forces of jets 16, 18, 20 and 22 together with the translational vectors of jets 26 and 28 will act with respect to corner 9 causing the sheet to translate leftward and at the same time then rotate in a counterclockwise direction placing the edge defined by corners 7 and 9 of sheet 8 against the reference edge for accurate positioning. When the force of the sheet 8 against reference edge 14 is sufficient to overcome the translational effects of those jets still acting on it, the forward vector will translate the sheet until jets 30, 32 and 34 engage it. As can be seen from FIG. 1, the angular orientation of jets 30, 32 and 34 is still such that they form a small acute angle with respect to the reference edge but such that the translational force vectors created thereby are small with respect to the forward transporting vector. Thus a force is exerted on sheet 8 to keep the edge thereof abutted against edge aligner 14 or reference edge 14 and at the same time provide a substantial forward moving force to transport the paper out of the transporter and aligner apparatus. After the paper 8 leaves the transport mechanism and is aligned against the reference edge 14, the sheet may be transported to any other utilizing device as for example a collator or sorter.
FIG. 3 more clearly illustrates the use of tube type jets 44 extending through openings 42 in the top and bottom restraining means 10 and 12. The tubes are angled to form converging air flows and provide, in the transport region between restraining means 10 and 12, a low pressure or Bernoulli effect which will have the effect of towing the paper in the air flow and not on the restraining means 10 or 12. The configuration shown in FIG. 3 illustrates the use of jets protruding through openings and these jets are supplied from an accumulator or plenum 50 which is in turn supplied with pressurized air from a pump 52.
FIG. 2 illustrates an alternative embodiment wherein the upper and lower restraining means have been formed as part of a plenum chamber 54 which is pressurized by pump 52. The jets are then formed by holes being drilled at the appropriate angular orientation both with respect to the paper path and also slanted in the direction of travel desired by the paper at any one point to cause converging Bernoulli air flows to urge the paper forward.
Particular advantages of this type of system over mechanical systems is that the paper is free to overcome the forces of the jets when it engages a rigid alignment member such as the reference edge and not crumple, tear or otherwise mutilate the paper where a mechanical device is in firm physical contact with the page may create tears, wrinkles, or crumpling of the sheet, and resulting paper jams.
An additional reason for utilizing this mechanism over a mechanical device would be its relatively inexpensive construction inasmuch as there are very few moving mechanical parts, primarily confined to the pressure pump. Additionally the positive air flow through jets does not require an air filtering system such as vacuum transports, the type of mechanism which can become contaminated by the entraining of contaminate particles such as dirt or paper dust in the air flow.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.