Vacuum side-folder section for envelope blank folding apparatus

Abstract: An envelope forming apparatus has a vacuum table (36) with apertures (48) through which a vacuum is applied onto the surface of the vacuum table. A series of parallel endless belts (42) move across the vacuum table and transport an envelope blank across the vacuum table. The vacuum through the apertures in the vacuum table holds the blank on the belts as they move across the vacuum table and as the blank is folded by a plowshare folder located relative to the vacuum table. Alternatively, a single wide belt with apertures may be substituted for the series of parallel belts.

Description: This invention relates to an envelope folding machine, and more particularly, to an envelope folding machine for forming envelopes which includes a vacuum table with a plurality of belts moving across the vacuum table to hold and transport the envelope blank through a folder in the folding apparatus. In automated envelope forming operations, it is well known to provide a folding machine which includes plowshare type folding mechanisms positioned on the folding machine for folding the envelope blanks along the longitudinal axis of movement of the blank while the blank is controlled and moved past the plowshares by means of rollers. The use of a vacuum to hold and transport envelope blanks in envelope making machines is also well known in the art. US Patent No. 3,288,037 discloses a rotary envelope making machine including a section for folding the side flaps of an envelope blank. Envelope blanks are transported through a folding section on the surface of a conveyor belt having a plurality of perforations extending through the belt overlying a trough. A vacuum is maintained in the trough so that as the belts pass over the trough air is sucked through the perforations to seize the envelope blanks to the surface of the belt and hold them in place while the blanks are folded. French Patent No. 1,231,917 discloses a punching machine for use in manufacturing folded boxes and like articles manufactured from cardboard or similar materials where a web of material is conveyed and stopped periodically for punching or cutting. The web is driven by endless belts which engage the web by suction. During the punching or cutting operations the web is held in fixed position in relation to the moving belts by a clamping device positioned above the belts. The belts are perforated and run over slots in a suction box positioned below the belts. The slots in the box communicate with the perforations of the belts so that the negative pressure generated in the suction box is applied to the surface of the belts. The web is pressed against the belts by the difference between the atmospheric pressure and the negative pressure or suction acting through the perforations in the belts. The web is conveyed by the belts which are spaced a preselected distance apart on the surface of the suction box. When the web is to be stamped or cut a clamping device presses the web against the surface of the box. The clamping device is positioned between the belts so that it does not engage the belts which continue to move with the web remaining stationary. When the punching or cutting operation is completed the clamp is raised out of contact with the web so that the web engaged by the suction force to the belts moves with the belts. U.S. Patent No. 2,037,561 discloses an endless conveyor belt with perforations for receiving instrumentalities wrapped in gauze with free ends of the gauze forming leading and trailing end flaps. A suction nozzle grasps the leading end flap and pulls it over the body of the instrumentality while a blower opposite the suction source blows the gauze upwardly to lift the leading end flap away from the conveyor and toward the suction nozzle. The mechanism is duplicated for acting on the opposite end flap and provision is made for a means to transfer the instrumentalities from one conveyor to another. U.S. Patent No. 2,754,113 discloses a sheet folding machine wherein the material to be folded is fed onto two parallel central conveyor belts which raise the material at the sides such that the center section of the material is conveyed beneath a plate. As the material passes beneath the plate it is clamped and the sides are folded over by cross plates. The article is thereafter passed over a cross folding roll above which is positioned an air blast pipe which is operated to send a blast of air against the material and force the material between rolls to provide a crossfold after which it is conveyed to a stacker. U.S. Patent No. 2,846,215 discloses a device utilizing rolls with vacuum apertures to grip and fold endless bands of paper. U.S. Patent No. 3,685,818 discloses a method for folding diapers on a collapsible suction plate with hinged sections corresponding to the folded portions of the articles to be folded. A pair of suction discharge rolls remove the diapers from the suction plate and transport them to a packaging carton. U.S. Patent No. 3,870,292 discloses the use of rolls with apertures connected to a vacuum source to transport and fold a continuous web of paper. U.S. Patent No. 4,682,977 discloses an apparatus for folding side flaps inwardly in a continuous web of material. The continuous web is cut by a die roll pair transversely to the longitudinal axis of the web. The web of material is held between a vacuum belt and a friction belt, and the flaps formed by the die roll pair are folded by friction belts at an angle to the longitudinal axis of the material to be folded. U.S. Patent No. 4,549,728 discloses a vacuum table having at least one row of apertures which is used to apply a vacuum to a sheet of paper as it approaches a head stop, to slow the paper before it reaches the head stop to prevent wrinkles and inaccurate folds. When the paper reaches the head stop, a chopper folder introduces the paper between two fold rollers turning in opposite directions to fold the paper. Although the prior art discloses the use of a vacuum to grip and move either a sheet or web of material, as well as a vacuum for slowing the forward advancement of a sheet of material, there remains a need for a vacuum table used in conjunction with a plowshare type folding device to better perform the controlling function of the blank as it passes through the folder area and to simplify the construction of the envelope blank folding apparatus to enable the operator to more easily adjust and maintain the apparatus. In accordance with the present invention there is provided a vacuum table folding apparatus that includes a vacuum chamber having an upper surface with a plurality of apertures therethrough for drawing air into the vacuum chamber. A plurality of parallel continuous endless belts extend in overlying relation with the apertures in the vacuum table upper surface for supporting envelope blanks. The belts are separated from one another by spaces. Means is provided for moving the belts across the upper surface as air is drawn into the vacuum chamber through the apertures to in turn draw air through the spaces between adjacent belts to adhere the envelope blanks to the belts. Folding means is positioned above the belts for folding the envelope blanks as the blanks are held on the belts by vacuum from the vacuum chamber. Further in accordance with the present invention there is provided a method of folding envelope blanks that includes the steps of providing a vacuum chamber having an upper surface with a plurality of apertures therethrough. A plurality of endless belts are rotatably supported in spaced parallel relation in overlying relation with the vacuum chamber. The belts are rotated to move the belts across the vacuum chamber upper surface. Air is drawn into the vacuum chamber through the apertures to adhere envelope blanks to the surfaces of the belts as air passes through spaces between adjacent belts into the vacuum chamber. The envelope blanks are folded as the envelope blanks pass over the vacuum chamber and are held onto the belts by air flowing downwardly between the belts into the vacuum chamber. The belts carry the envelope blanks across the vacuum table into contact with plowshare folding apparatus. The vacuum applied through the apertures in the vacuum table adjacent to the belts causes a suction to be applied to the spaces between the belts to hold the blanks onto the belts. Figure 1 is a perspective view of the envelope making machine and incorporated the vacuum table with side folders. Figure 2 is a view of in side elevation of the envelope making machine and incorporating the vacuum table with a plowshare folder. Figure 3 is perspective view of a vacuum box with portions broken away to illustrate the feature of the vacuum box. Figure 4 is a perspective view of the drive side plowshare. Figure 5 is a perspective view of the operator side plowshare. Figure 6 is a detail of the height adjustment apparatus for the plowshares exit end. Figure 7 is a plan view of the table plate at the entry end of the present invention. Figure 8 is a view in section taken along line 8-8 in figure 7 and illustrating the table plate receiving the tip of a plowshare in a groove in the table plate. DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings, and particularly to figures 1 and 2, there is illustrated an envelope forming machine generally designated by the numeral 10 for use in forming envelopes from blanks of paper. Envelope forming machine 10 includes a vacuum feed 12 for transferring the blanks 14 from the stack of blanks to the disk drive and separator mechanism 16. From the disk drive and separator mechanism 16 the blank 14 is moved through envelope forming machine 10 to the outside printers 18 and then to the inside printer 20. Top and bottom score mechanism 22 scores the blank 14, which is then transferred to a side score mechanism 24, and from the side score mechanism 24 the blank 14 is moved to a center seal gummer 26. From the center seal gummer 26 the blank 14 is transferred to a vacuum table folding device generally designated at 28 which is the object of the present invention and which will be described in greater detail hereinbelow. From the vacuum table folding device 28 the blank 14 is picked up by creasing rollers 30 which crease the folds in the blanks 14 made by the vacuum table folding device 28. A side seam gummer 32 applies glue to the side seams of the blank 14, and a bottom flap gummer 34 applies glue to the bottom flaps of the blanks 14. Bottom flap folder 35 folds the bottom flap of blank 14. Referring to figures 1 and 2, the vacuum table folding device 28 illustrated is a vacuum table generally designated at 36 with a pair of plowshare folders 38 supported in overlying relation to the vacuum table 36 by means of a beam 40. Belts 42 are driven across the vacuum table 36 to effect movement of blanks 14 across the vacuum table 36 and into contact with the plowshare folders 38. The belts 42 are guided and driven by rollers 44 which are in turn driven by an appropriate drive mechanism. Referring to figure 3, which illustrates vacuum table 36 with portions thereof broken away, a plurality of parallel continuous endless belts 42 extend around rollers 44, which are driven by appropriate drive mechanisms. The upper surface 46 of the vacuum table 36 has a plurality of apertures 48 which draw in air as a result of the vacuum created by the evacuation of air from the vacuum box 36 via pipes 50. The pipes 50 are connected vacuum creating mechanism. Vacuum table 36 is connected to the envelope forming machine 10 by means of connecting members 52 which are bolted to the frame 54 of the envelope machine 10 and also bolted to the frame 56 of the vacuum table 36. As the belts 42 are driven across the upper surface 46 of the vacuum table 36, air drawn into the vacuum box 36 through the apertures 48 in the upper surface cause the blanks 14 to adhere to the belts 42 as the air being drawn into the vacuum box 36 must pass through the space 58 between adjacent belts 42. Referring to figures 4 and 5, there is illustrated the plowshare folding device 38 which is located relative to the vacuum table 36 by means of beam 40. The direction of movement of paper on the plowshare folding device 38 is indicated by the arrows, and as the blank 14 moves across the vacuum table 36 on the belts 42, the plowshare folders 38 engage the side flaps of the blank 14 and fold them up and over the main body of the blank 14. The tips or front ends 60 of the plowshares 38 are angled downwardly and fit into recesses 62 in plate 64 which extends transversely to the axis of movement of the blanks 14 across the vacuum table 36, as will be more fully described hereinbelow. The plowshares 38 are a thin wall of rigid material which have at their front end an initially planar surface and which gradually bend toward each other in a 180° turn to engage the ends of the blanks 14 parallel to the axis of movement of the blanks 14 across the vacuum table 36 and to fold the side portions of the blanks 14 over the main body surface of the blanks 14 opposite the vacuum table 36. The rear end 70 of the plowshares 38 are supported on the vacuum table 36 above the belts 42 by means of a height adjustment 66. As illustrated in figure 6, height adjustment clamp 66 has a screw set 68 permitting adjustment of the height of the rear end 70 of the plowshare 38 to prevent the rear end 70 of the plowshare 38 from abrading the belts 42. Figure 7 illustrates the plate 64 into which the front ends 60 of the plowshares 38 fit into the recesses 62. Plate 64 has a series of indentations 72 to accommodate the rollers bearing the belts. The front edge of plate 64 slides under the preceding station acting upon blanks 14 to facilitate the smooth transition of the blanks 14 from the preceding station. Figure 8 is a view of the tip 74 of plowshare 38 fitting into the recess 62 in the plate 64 and the plate 64 receiving a blank 14 from the preceding station. According to the provisions of the Patent Statutes, we have explained the principal, preferred construction and mode of operation of our invention and have illustrated and described what we now consider to represent its best embodiments. However, it should be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Claims: A vacuum table folding apparatus comprising, a vacuum chamber (36) having an upper surface (46) with a plurality of apertures (48) therethrough for drawing air into said vacuum chamber (36), characterized by a plurality of parallel continuous endless belts (42) extending in overlying relation with said apertures (48) in said vacuum table upper surface (46) for supporting envelope blanks (14), said belts (42) being separated from one another by spaces (58), means (44) for moving said belts (42) across said upper surface (46) as air is drawn into said vacuum chamber (36) through said apertures (48) to in turn draw air through said spaces (58) between adjacent belts (42) to adhere the envelope blanks (14) to said belts (42), and folding means (38) positioned above said belts (42) for folding the envelope blanks (14) as the blanks (14) are held on said belts (42) by the vacuum from said vacuum chamber (36). A vacuum table folding apparatus as set forth in claim 1 in which, said folding means includes a pair of plowshare type folders (38). A vacuum table folding device as set forth in claim 1 in which, said means for moving said belts (42) across said vacuum table upper surface (46) includes a pair of rollers (44) rotatably supported at opposite ends of said vacuum table upper surface 46, said endless belts (42) reeved around said rollers (44), and said rollers (44) being rotatably driven to drive said belts (42) across said vacuum table upper surface 46. A vacuum table folding apparatus as set forth in claim 2 which includes, a plate (64) transverse to the axis of movement of said belts (42), said plate (64) having a recess (62) transverse to the axis of movement of said belts (42), and the tip (60) of each of said plowshares (38) fitting into said recess (62). A vacuum table folding apparatus as set forth in claim 2 in which, the rear end (70) of each of said plowshares (38) having means (66,68) for moving said rear end (70) of at least one of said plowshares (38) toward or away from said belts (42). A vacuum table folding device as set forth in claim 3 in which, said belts (42) extend across said vacuum table upper surface (46) in the direction of movement of the envelope blanks (14) through said folding means (38). A method of folding envelope blanks comprising, providing a vacuum chamber (36) having an upper surface (46) with a plurality of apertures (48) therethrough, characterized by rotatably supporting in spaced parallel relation a plurality of endless belts (42) in overlying relation with said vacuum chamber (36), rotating said belts (42) to move said belts (42) across said vacuum chamber upper surface (46), drawing air into said vacuum chamber (36) through said apertures (48) to adhere envelope blanks (14) to the surface of said belts (42) as air passes through spaces (58) between adjacent belts (42) into said vacuum chamber (36), and folding said envelopes blanks (14) as said envelope blanks (14) pass over said vacuum chamber (36) and are held onto said belts (42) by air flowing downwardly between said belts (42) into said vacuum chamber (36).

Inventors: HIMMEL RONALD G, PROUGH DENNIS G, SMITHE ELIOT S, HIMMEL, RONALD G., PROUGH, DENNIS G., SMITHE, ELIOT S.
Applicants: SMITHE MACHINE CO INC F L, F.L. SMITHE MACHINE COMPANY INC.
Application year: 1992
Main classification: B31B19
IPC codes: B65H45