Abstract:
A method and system for folding a sheet having a certain length into a folded piece of a fold type having a first edge and a second edge, wherein the sheet length and the fold type are simultaneously selectable. The sheet can be folded once or twice into the folded piece. After the sheet is folded into the folded piece, the folded piece moves in a direction with a first edge leading the second edge. The method and system further include a step and a mechanism to control the moving direction of the folded piece such that the folded piece can be caused to move with the first edge trailing the second edge or allowed to continue to move with the first edge leading the second edge when the folded piece exits the system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Reference is made to application Ser. No. 09/442,559, entitled METHOD AND SYSTEM FOR DIRECTING AN ITEM THROUGH THE FEED PATH OF A FOLDING APPARATUS, assigned to the assignee of this application and filed on the even date herewith. 
     Reference is made to application Ser. No. 09,442,552, entitled METHOD AND SYSTEM FOR TABBING FOLDED MATERIAL, assigned to the assignee of this application and filed on the even date herewith. 
     Reference is made to application Ser. No. 09,442,561, entitled METHOD AND SYSTEM FOR FOLDING AND TABBING SHEETS, assigned to the assignee of this application and filed on the even date herewith. 
    
    
     TECHNICAL FIELD 
     The present invention is generally related to a folding apparatus for folding a sheet of a document into a folded piece and, in particular, to a folding apparatus wherein the folded piece can be directed to an envelope inserting machine to be inserted into an envelope, or to a tabbing apparatus to be sealed and used as a self-mailer. 
     BACKGROUND OF THE INVENTION 
     A self-mailer is conventionally defined as a mailpiece without an envelope. The self-mailer usually contains one or more sheets of printed material, folded once or twice by a folding machine into a smaller piece for mailing. Typically, the folded piece has a folded end and an open end (see FIGS.  11 - 14 ). The open end is sealed with one or more tabs before the self-mailer is sent to the addressee. 
     Folding machines are well-known. For example, U.S. Pat. No. 4,701,233 (Beck et al.) discloses a method of folding a sheet by bulging a portion of the sheet and then folding the bulged portion through a roller nip. U.S. Pat. No. 4,875,965 (Marzullo) discloses a folding apparatus wherein a buckle chute is used for stopping a sheet, causing the sheet to enter a roller nip for folding. U.S. Pat. No. 4,944,131 (Gough) also discloses a folding apparatus having a buckle chute. With the above-identified folding machines, when the folded piece exits the folding apparatus, it travels in the direction of the fold. This means that the folded end is leading the open end. Folding machines are generally designed for folding enclosure material to be inserted into envelopes in an envelope inserting device. In this particular application, the traveling direction of the folded piece is not very important. But for tabbing purposes, it is desirable that the folded piece travels with the open end leading the folded end. Thus, while the traveling direction of the folded piece exiting a prior art folding machine is suitable for envelope insertion, it is not suitable for tabbing. 
     It is advantageous and desirable to provide a method and an apparatus for folding sheets wherein the leading edge of the folded piece exiting the folding apparatus can be selected. Furthermore, it is advantageous and desirable to provide a method and apparatus for folding sheets wherein the length of the sheet to be folded and the type of fold for the folded piece can be easily selected. 
     SUMMARY OF THE INVENTION 
     The first aspect of the present invention is to provide an apparatus for folding a sheet having a certain length into a folded piece of a fold type having a first edge and an opposing second edge, wherein the apparatus includes a selecting mechanism to select he sheet length and the fold type, and a path directing mechanism to allow the folded piece to exit the folding apparatus with the first edge trailing or leading the second edge. 
     Accordingly, the folding apparatus of the present invention has a plurality of settings for selecting different fold types and selecting different sizes of the sheet to be folded. The folding apparatus comprises: a folding station, a feeding mechanism to feed the sheet into the folding station in order to fold the sheet into a folded piece; a turn chute having an ingesting nip to ingest the folded piece into the turn chute with the first edge leading the second edge, and an exiting nip to move the ingested folded piece out of the turn chute with the second edge leading the first edge. 
     Preferably, the folding station comprises: a first buckle chute for receiving the sheet fed into the folding station and folding the fed sheet into a folded sheet, a second buckle chute, and a deflector gate operable at a first gate position and a second gate position, wherein when the deflector gate is operated at the first gate position, the deflector gate causes the folded sheet to be ingested into the turn chute directly from the first buckle chute, and when the deflector gate is operated at the second gate position, the deflector gate allows the folded sheet to enter the second buckle chute to be folded again into the folded piece. 
     Preferably, the turn chute also includes a direct exit, and a reversing stop operable at a first position and a second position, wherein when the reversing stop is operated at the first position, the reversing stop causes the ingested folded piece to be engaged with the exiting nip so as to allow the exiting nip to move the ingested folded piece out of the turn chute with the second edge leading the first edge; and when the reversing stop is operated at the second position, the ingested folded piece is allowed to exit through the direct exit with the first edge leading the second edge. 
     Preferably, the reversing stop in the turn chute is adjustable to suit the fold type and the sheet length; and the first buckle chute is adjustable to suit the fold type and the sheet length; and the folding apparatus further includes a selecting mechanism linking to the first buckle chute, the reversing stop in the turn chute and the deflector gate for simultaneously selecting the operating position of the deflector gate and adjusting the first buckle chute and the reversing stop in order to suit the fold type and the sheet length in accordance with the settings. 
     The second aspect of the present invention is to provide a method of folding a sheet having a certain length into a folded sheet of a fold type. The folding method comprises the steps of: providing the sheet to be folded; folding the sheet into a folded piece having a first edge and an opposing second edge, wherein the folded piece moves in a direction with the first edge leading the second edge after the sheet is folded; and controlling the moving direction of the folded piece so that the first edge leads or trails the second edge. 
     Preferably, the folding step is carried out in a buckle chute that makes a single fold and has a sheet stop for selecting the fold type and the sheet length, and the controlling step is carried out in a turn chute having a reversing stop adjustable to suit the fold type and the sheet length, wherein the sheet stop and the reversing stop are linked to a turn knob for simultaneously adjusting the reversing stop and sheet stop to suit the fold type and the sheet length. 
     Preferably, the folding step is further carried out in a second buckle chute for making a second fold if required. 
     It is also preferred that the turn chute has a direct exit and a reversing exit, and the reversing stop is operable at a first position to cause the folded piece to exit through the reversing exit with the second edge leading the first edge, and a second position to allow the folded piece to exit through the direct exit with the first edge leading the second edge. 
     The method and apparatus for folding a sheet into a folded piece, according to the present invention, will become apparent upon reading the description taken in conjunction with FIG. 1 to FIG.  14 . 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a self-mailer producing machine showing a folding apparatus and a tabbing apparatus. 
     FIG. 2 is a schematic representation of a self-mailing producing machine showing the different paths for the folded piece to exit the folding apparatus, according to the present invention. 
     FIG.  3 A and FIG. 3B are diagrammatic representations that illustrate the operating principle of the turn chute. 
     FIG. 4 is a schematic representation of the folding apparatus showing the relative position of the adjustable components of the folding apparatus when the folding apparatus is set up for making a Z-fold. 
     FIG. 5 is a schematic representation of the folding apparatus when the folding apparatus is set up for making a single fold from a sheet of document having a length of 14″ (355.6 mm). 
     FIG. 6 is a schematic representation of the folding apparatus when the folding apparatus is set up for making a double fold. 
     FIG. 7 is a schematic representation of the folding apparatus when the folding apparatus is set up for making a single fold from a sheet of document having a length of 11″ (279.4 mm). 
     FIG. 8 is a schematic representation of the folding apparatus when the folding apparatus is set up for making a single fold from a sheet of document having a length of 8″ (203.2 mm). 
     FIG. 9 is a schematic representation of the folding apparatus when the folding apparatus is set up for making a C-fold. 
     FIG. 10 is a schematic representation of the folding apparatus when the folding apparatus is set up for making a Z-fold but the folded piece is allowed to exit the folding apparatus in a different manner as compared to the setting shown in FIG.  4 . 
     FIG. 11 is a schematic representation of a folded piece with a Z-fold. 
     FIG. 12 is a schematic representation of a folded piece with a single-fold. 
     FIG. 13 is a schematic representation of a folded piece with a double-fold. 
     FIG. 14 is a schematic representation of a folded piece with a C-fold. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a typical self-mailer producing machine  200  which comprises a folding apparatus  10  and a tabbing apparatus  12 . The folding apparatus  10  takes in a sheet of document  120  (see FIG. 2) at an entrance end  202  and folds the sheet into a folded piece  130  (see FIG.  2 ). The folded piece  130  is then moved to the tabbing apparatus  12  where a tab is put on the leading edge of the folded piece  130  to seal the folded piece  130  into a self-mailer  140  (see FIG.  2 ). The sealed folded piece, or the self-mailer  140 , is moved out of the tabbing apparatus  12  at an exit end  206 . 
     As shown in FIG. 2, the folding apparatus  10  has a feed roller  30  for picking up one sheet of document  120  at a time from a paper tray or cassette  150 . The sheet of document  120  is moved into a folding station  60  through a nip  32  formed by rollers  34  and  36 . After the sheet  120  is folded into a folded piece  130 , it is ingested into a turn chute  90  by rollers  36  and  44 . Inside the turn chute  90 , a turn chute stop  92  is used to stop the ingested folded piece  130  and cause the folded piece  130  to be moved out of the turn chute  90  by rollers  44  and  48 . After the folded piece  130  is moved out of an exit end  204  of the folding apparatus  10 , it is moved towards the tabbing apparatus  12  along a moving path  160 . After the folded piece  130  is sealed by the tabbing apparatus  12 , it becomes a self-mailer  140  and is moved out of the tabbing apparatus  12  at the exit end  206 . 
     As shown in FIG. 2, the folding station  60  includes a first buckle chute  70  and a second buckle chute  80 . If the folded piece  130  is required to be folded only once, then only the first buckle chute  70  is used for folding the sheet  120 . It is followed that the folded piece  130  is moved directly from the first buckle chute  70  into the turn chute  90 . If the folded piece  130  is required to be folded twice, then the sheet  120  is folded once by the first buckle chute  70  and then moved into the second buckle chute  80  for the second fold before the folded piece  130  is ingested into the turn chute  90 . 
     It is possible to move the folded piece  130  out of the folding apparatus  10  through another path  162  at the exit end  208  of the turn chute  90  by removing the turn chute stop  92  from the path of the ingested folded piece  130 . In that case, the folded piece  130  can be directed towards another machine such as an envelope inserting machine where the folded piece  130  is inserted into an envelope for mailing, or a printer, or a labeler for putting on an address label, etc. 
     FIGS. 3A and 3B diagrammatically illustrate the operating principle of the turn chute  90 . As shown in FIG. 3A, the folded material  130  is drawn into the turn chute  90  by an ingesting nip  42  formed by the rollers  36  and  44 . Originally, the paper lift roller  54 , which is spring-loaded, is at an upright position. As the leading edge  132  (the folded end) of the folded material  130  is moved into the turn chute  90 , it depresses the paper lift roller  54  until the leading edge  132  is stopped by the turn chute stop  92  (shown diagrammatically). Even after the leading edge  132  of the folded piece  130  is stopped by the turn chute stop  92 , the trailing edge  134  (the open end) of the folded piece  130  is still drawn into the turn chute  90  by the ingesting nip  42 . Because the distance between the turn chute stop  92  and the ingesting nip  42  is slightly shorter than the length of the folded piece  130 , the trailing edge  134  of the folded piece  130  starts to buckle and the paper lift roller  54  starts to move back to its original position. Once the trailing edge  134  of the folded piece  130  is disengaged from the ingesting nip  42 , with the help of the rotating roller  44  and the urging force of the returning paper lift roller  54 , the open end  134  of the folded piece  130  is raised and moved toward the roller  48 . Because the distance between the turn chute stop  92  and the nip  46  formed by the rollers  44  and  48  is also slightly shorter than the length of the folded piece  130 , the open end  134  of the folded piece  130  is caused to be engaged with the nip  46 , as shown in FIG.  3 B. Subsequently, the folded piece  130  is moved out of the turn chute  90  by the rollers  44  and  48 , along the direction  160 . 
     Preferably, the turn chute stop  92  is operable at a closed position and an open position (shown with phantom lines in FIG.  3 A), so that when the turn chute stop  92  is operated at the open position, the folded piece  130  is allowed to move out of the turn chute  90  through the direct exit  208  along the direction  162  with the folded end  132  leading the open end  134 . 
     Now referring to FIG. 4, the first buckle chute  70  comprises a lower sheet guide  72 , a sheet stop  74 , and a first folding nip  38  formed by the rollers  36  and  40 . The location of the sheet stop  74  is adjustable so as to accommodate the length of the sheet  120  and the desired fold type for the folded piece  130 . Different fold types are illustrated in FIGS. 11-14. The second buckle chute  80  has an upper sheet guide  82 , and a fold stop  84 . The turn chute stop  92  in the turn chute  90  comprises a plurality of reversing stops  94   a ,  94   b  and  94   c , mounted on a common stop actuator  96 . In FIG. 4, there is shown a deflector gate  78  which can be operated at an open position and a closed position. When the deflector gate  78  is operated at the closed position, the sheet  120  folded by the first buckle chute  70  is directly ingested into the turn chute  90 . When the deflector gate is operated at the open position, it allows the sheet  120  folded by the first buckle chute  70  to enter the second buckle chute  80  for making a second fold. As shown in FIG. 3, the deflector gate  78  is operated at the open position. 
     In the preferred embodiment as shown in FIGS. 4-10, the position of the sheet stop  74 , the operating position of the deflector gate  78  and the turn chute stop  92  are controlled by a selector knob  56 . The selector knob  56  can be manually or electro-mechanically turned about a rotating axis  57  to select the setting according to the fold type and the sheet length. As shown, an adjustment gear  75  is linked to the selector knob  56  for adjusting the position of the sheet stop  74 . Also shown is a gate cam  62  linked to the selector knob  56  and a gate actuator  76  to control the operating position of the deflector gate  78 . Furthermore, a control rod  68  is used to move the reversing stop actuator  96  in order to select the operating position of the reversing stops  94   a - 94   c  and to adjust the distance between the reversing stops  94   a - 94   c  and the ingesting nip  42 .  65 . The control rod  68  is pivotably mounted on a lever  66  which is mounted at pivot point The lever  66  is pushed outward from the selector knob  56  by a stop cam  58 . The stop cam  58  and the gate cam  62  are fixedly mounted to the selector knob  56  so as to change the position of the deflector gate  78  and the reversing stops  94   a - 94   c  according to the position of the selector knob  56 . 
     As shown in FIG. 4, the selector knob  56  is set to a position for making a double-folded piece known as a Z-fold, as shown in FIG.  11 . With the Z-fold setting, the deflector gate  78  is operated at the open position so as to allow the folded sheet exiting the first buckle chute  70  to enter the second buckle chute  80  so as to be folded a second time before the folded piece  130  is moved into the turn chute  90 . As shown, the reversing stop  94   a  is used to stop the ingested folded piece  130  from exiting the turn chute  90  through the direct exit  208 . 
     As shown in FIG. 11, a folded piece  130  with a Z-fold is folded twice into three connecting sections denoted by sa, sb and sc having two folded edges f 1 , f 2 . In the setting as shown in FIG. 4, the distance between the first folding nip  38  and the sheet stop  74  is substantially equal to sa+sb. When a sheet  120  is moved by the entrance nip  32  into the first buckle chute  70 , it is stopped by the sheet stop  74 . As the entrance nip  32  continues to move the trailing end of the sheet  120  into the turn chute  70 , it causes the sheet  120  to buckle toward the first folding nip  38 . When the buckled section of the sheet  120  becomes engaged with the first folding nip  38 , the rollers  36  and  40  move the sheet  120  at the buckled point through the first folding nip  38  to make the first fold at the folded edge fi (see FIG.  11 ). The singly-folded sheet is moved further into the second buckle chute  80  in the direction of the folded edge f 1  until the folded edge f 1  is stopped by the fold stop  84 . As the rollers  36  and  40  continue to move the singly-folded sheet into the second buckle chute  80 , they cause the sheet  120  to buckle again and become engaged with the ingesting nip  42  of the turn chute  90 . The distance between the fold stop  84  and the ingesting nip  42  of the turn chute  90  is set to be substantially equal to sb. Then, the singly-folded sheet is pulled through the ingesting nip  42  into the turn chute  90 , making a second fold at the folded edge f 2  (FIG.  11 ). When the twice-folded piece  130  is moved into the turn chute  90 , it depresses the paper lift roller  54  so as to allow the entire folded piece  130  to enter the turn chute  90 . The entered folded piece  130  is stopped by the reversing stop  94   a . Because the distance between the reversing stop  94   a  and the ingesting nip  42  is slightly shorter than the length sb of the folded piece  130 , the trailing end  134  of the folded piece  133  is caused to move toward the exiting nip  46 . Subsequently, the exiting nip  46  moves the ingested folded piece  133  out of the turn chute  90 . In the particular fold setting of FIG. 4, sb=sc=3.75″ (95.25 mm) and sa=3.5″ (88.9 mm) for a sheet  120  with a length of 11″ (279.4 mm). 
     FIG. 5 shows the setting for making a folded piece with a single fold from a sheet having a length of 14″ (355.6 mm). The folded output is a C-fold, as shown in FIG. 12, with fold length sd=se=7.0″ (177.8 mm). As shown in FIG. 5, the selector knob  56  is now turned in the counter-clockwise direction from the position shown in FIG.  4 . The distance between the sheet stop  74  and the first folding nip  38  is set substantially equal to sd. Because only one fold is required to fold a sheet  120  into a folded piece  130 , the deflector gate  78  is now operated at the closed position so as to cause the folded sheet to be engaged with the ingesting nip  42  after the folded sheet exits the first folding nip  38 . The reversing stop  94   c  is used to stop the ingested folded piece  130  from leaving the turn chute through the direct exit  208 . The distance between the ingesting nip  42  and the reversing stop  94   c  is slightly less than sd. 
     In FIG. 6, the setting is set for a double-fold as shown in FIG. 13, with the length of the folded section being sf=2.75″ (69.85 mm), sg=sh=si=3.75″ (95.25 mm). The selector knob is set at a different position from the setting as shown in FIG.  5 . The distance between the sheet stop  74  and the first folding nip  38  is substantially equal to sf+sg to allow the first folding nip  38  to make the first fold between segments sg and sh. As with the setting for any folded piece that requires a second fold, the deflector gate  78  is operated at the open position so as to allow the folded sheet to enter the second buckle chute for making a second fold. The reversing stop  94   a  is again used to stop the folded piece  130  ingested into the turn chute. 
     FIG. 7 shows the folding apparatus  10  in the setting for a single fold, similar to the setting shown in FIG.  5 . The setting shown in FIG. 7 is for making a single fold from a sheet having a length of 11″ (279.4 mm). Accordingly, the distance between the sheet stop  74  and the folding nip  38  is shortened to about 5.5″ (139.7 mm). Furthermore, the reversing stop  94   b  is used to stop the ingested folded piece  130  in the turn chute  90 . The distance between the reversing stop  94   b  and the ingesting nip  42  is slightly shorter than 5.5″ (139.7 mm). 
     FIG. 8 shows another setting for a single fold, similar to FIGS. 5 and 7. The setting shown in FIG. 8 is for making a single fold from a sheet having a length of 8″ (203.2 mm). Accordingly, the distance between the sheet stop  74  and the folding nip  38  is further shortened to about 4″ (101.6 mm). Furthermore, the reversing stop  94   a  is used to stop the ingested folded piece  130  in the turn chute  90 . The distance between the reversing stop  94   a  and the ingesting nip  42  is slightly shorter than 4″ (101.6 mm). 
     FIG. 9 shows the folding apparatus  10  in the setting for making a C-fold, as shown in FIG.  14 . In particular, a sheet having a length of 11″ (279.4 mm) is folded into three sections sj=sl=3.625″ (92.075 mm), and sk=3.75″ (95.25 mm). The setting in FIG. 8 is similar to the setting in FIG. 4, except that the distance between the sheet stop  74  and the folding nip  38  is shortened to 3.625″ (92.075 mm), and the reversing stop  94   a  is used to stop the ingested folded piece  130  in the turn chute  90 . The distance between the reversing stop  94   a  and the ingesting nip  42  is shortened by the stop cam  58  to slightly less than 3.75″ (95.25 mm). 
     FIG. 10 shows that the folded piece  130  is allowed to exit the turn chute  90  through the direct exit  208 . As shown, a direct exit cam  98  which is rotatably mounted at pivot point  99  is used to push the reversing stop actuator  96  towards the ingesting nip  42 , disengaging the lever  66  from the stop cam  58 , and causing all the reversing stops  94   a - 94   c  to move out of the path  162  of the ingested folded piece  130 . As described in conjunction with FIG. 3A above, when an ingested folded piece  130  exits the turn chute  90  through the direct exit  28 , its leading edge is the same edge as that when it is ingested into the turn chute  90 . 
     It should be noted that the orientation of the direct exit  98  is not linked to the position of the selector knob  56 . A folded piece of any fold type can be allowed to exit the turn chute  90  through the direct exit  208  if so desired. 
     Although the invention has been described with respect to the preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and various other changes, omissions and deviations in the form and detail thereof may be made without departing from the spirit and scope of this invention.