Abstract:
A feeder head assembly is provided for transporting a material in a printing apparatus. The feeder head assembly includes a housing and a cap. The housing is at least partially rotatable about a longitudinal axis. Also, the housing includes an inner hollow chamber and an opening into the chamber. The inner hollow chamber is adapted to be in fluid communication with a vacuum source for decreasing pressure within the chamber. The opening is defined by a rim. The cap is removeably secured to at least a portion of the rim. The cap includes at least one aperture passing therethrough, wherein the at least one aperture is in fluid communication with the vacuum source.

Description:
The present application claims priority to provisional patent Application Ser. No. 60,711,729, filed Aug. 26, 2005. This earlier filed provisional application is incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a device for transporting a printable material within a printing machine, and more particularly a device for transporting a printable material using vacuum. 
   Vacuum assisted material handling assemblies are often used for manipulating sheets of print material, such as paper, envelopes, labels, etc. In particular, vacuum assisted rollers are desirable in high-speed printing applications, where it is important that one sheet be picked-up and transported at a time. Contemporary vacuum assisted feeder heads use a rotatably mounted cylindrical body having surface apertures. The apertures are coupled to a vacuum source and are used to create a negative surface pressure for picking up and moving the print material. The ability of the feeder head to properly engage and retain pieces of print material is correlated to surface texture of the feeder head engagement surfaces, as well as the size and configuration of the apertures, the vacuum source and feeder head itself. 
   Variations in print material and general maintenance often demand changes in the surface texture or aperture configuration on the feeder head. For example, the material engagement surface of the feeder head may be worn down or a larger or different aperture is needed. However, in order to change or repair the surface texture or aperture configuration on the feeder head, traditionally the entire cylindrical feeder head body needs to be removed and replaced. Such repairs and/or changes are difficult and often involve the neighboring assembly in the printing apparatus. Some more recent feeder heads include an outer sleeve or plate that has its own apertures that align with the apertures on the more traditional feeder head. However, the outer sleeve/plate aperture profile is limited by the size and configuration of the underlying cylinder apertures. Thus, more extensive surface or aperture profile changes once require the replacement of the entire feeder head. 
   Thus, it is desirable to provide a device for transporting a printable material which overcomes the shortcomings found in the art of material transfer assemblies as set forth above while also providing improved structural and operating features. 
   SUMMARY OF THE INVENTION 
   The present invention provides a feeder head assembly for transporting a material in a printing apparatus. The feeder head assembly includes a housing and a cap. The housing is at least partially rotatable about a longitudinal axis. Also, the housing includes an inner hollow chamber and an opening into the chamber. The inner hollow chamber is adapted to be in fluid communication with a vacuum source for decreasing pressure within the chamber. The opening is defined by a rim. The cap is removeably secured to at least a portion of the rim. The cap includes at least one aperture passing therethrough, wherein the at least one aperture is in fluid communication with the vacuum source. 
   Additionally, alternative aspects of the present invention can include an opening rim having at least a portion extending longitudinally across a portion of the housing. Also, the hollow chamber can include portions of disposed on opposed sides of the longitudinal axis. Further, the at least one aperture can include a plurality of apertures aligned in at least one row. Further still, the opening can have different dimensions and/or a different configuration from that of the at least one aperture. Yet further, the assembly can further include a shaft supporting the housing and adapted to rotate the housing between a first an second position. 
   Additionally, further alternative aspects of the present invention can include the cap having a perimeter and at least a portion thereof disposed on at least a portion of the rim. Also, an inner portion or inner hollow region of the cap can define at least a portion of the inner hollow chamber; or the cap can include a trough which forms an extension of the inner hollow chamber. Further, the cap can be removed from the feeder head in a radial direction from the longitudinal axis. Further still, at least a portion of the cap can define at least a portion of an axial end of the feeder head assembly. Yet further still, the cap can include at least one projection extending from the cap into the opening toward the chamber. 
   The present invention further provides a feeder head assembly including a cap and a housing at least partially rotatable about a longitudinal axis. The housing includes an inner hollow chamber and an outer opening into the chamber. The inner hollow chamber is adapted to be in fluid communication with a vacuum source for decreasing pressure within the chamber. The opening extends longitudinally across a substantial portion of the housing. The cap is removeably secured to the housing and covers at least a portion of the opening. The cap includes at least one aperture passing therethrough, wherein the at least one aperture is in fluid communication with the vacuum source. 
   The present invention further provides an assembly for transporting a material in a printing apparatus. The assembly includes a printing unit, a shaft, a feeder head and a vacuum source. The shaft is at least partially rotatable about a longitudinal axis. The feeder head is supported by the shaft for conveying the material toward the printing unit. The feeder head includes an outer housing and a cap. The housing and the cap defining a hollow chamber. The housing including an outer opening in the housing extending into the hollow chamber. At least a portion of the opening extends longitudinally across a portion of the housing. Also, the cap is removeably secured to the housing and includes at least one aperture passing therethrough. Further, the at least one aperture is disposed over the opening. The vacuum source decreases pressure within the hollow chamber. Also, the vacuum source is in fluid communication with the chamber and the at least one aperture. 
   Additionally, further alternative aspects of the present invention can include the cap being adapted to be removed from the housing without removing the feeder head from the shaft. Also, the cap can be adapted to be removed from the housing while the feeder head remains secured within the printing apparatus. Further, the assembly can include a drive mechanism coupled to the shaft, wherein the drive mechanism is adapted to move the feeder head between a first position and a second position. 
   It is therefore desirable to provide a device for transporting a printable material that is easy to maintain and/or alter to suit numerous printing jobs. In particular, one aspect of the present invention provides a feeder head assembly that is easily reconfigured and does not require the removal of the entire feeder head from the printing apparatus. Another aspect of the present invention provides a feeder head cap whose apertures are not limited by an aperture configuration on the underlying main feeder head housing. Yet another aspect of the present invention provides a feeder head cap that can easily replaced with a cap of a different design to adjust the vacuum profile and/or engagement of print material on the feeder head assembly. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of a printing press with a material feeder. 
       FIG. 2  is a top plan view of the material transport device of the present invention in the feeder of a printing press. 
       FIG. 3  is a cross-sectional view of the material feeder taken along line  3 - 3  of  FIG. 2 . 
       FIG. 4  is a top perspective view of portions of the assembly of the present invention. 
       FIG. 5  is an exploded perspective view of the assembly of  FIG. 4 . 
       FIG. 6  is a top plan view of the assembly of  FIG. 4 . 
       FIG. 7  is an elevational end view of the assembly of  FIG. 4 . 
       FIG. 8  is a top plan view of the assembly of  FIG. 4  with the cap removed. 
       FIGS. 9A-F  are perspective views of various embodiments of the cap of the present invention. 
       FIG. 10  is a prospective view of the bottom side of the cap of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention includes a material transfer device that uses vacuum to hold a piece of material and transport it between a first and second position. In the preferred embodiment, the transfer device may be used in a printing press for transporting pieces of printable material, such as envelopes or sheets of paper. Such a printing press is manufactured by Halm Industries Co., Inc. of Glen Head, N.Y. under the trademark JET PRESS®. It is also within the contemplation of the present invention that the transfer device may be used in other types of machines in which sheets of material are moved such as mail sorters or copying machines. 
   With reference to FIGS,  1 - 3 , a printing press  10  of a type well known in the art typically includes a feeder  12  having a portion  13  which can hold a stack of pieces of printable material  14 . This material may be in the form of envelopes, sheets of paper or other material such as plastic, or other printable material. The feeder transports the printable material from the stack into a printing station  16  of the machine wherein an image is transferred to the printable material. Once printed, the material is transferred to an output table  18  where it can be stacked and await removal from the machine by an operator. The present invention relates to the material transfer device  20  which preferably forms part of the feeder  12 . The material transfer device or feeder head assembly  20  is disposed below the material holding portion  13  of the feeder such that it is positioned at the bottom of the stack of printable material  14 . The feeder head assembly  20  preferably uses a vacuum source to engage and grip the piece of printable material  14  on the bottom in the stack. The feeder head assembly  20  then rotates from a first position to a second position thereby moving the material from the stack onward toward the printing station  16 . In the preferred embodiment, the feeder head assembly  20  rotates less than a full 360 degrees and reciprocates back and forth between the first and second position in order to move a piece of printable material. In an alternative embodiment, the transfer device  10  could continuously rotate in order to transport the printable material. The mechanism may be reciprocated by a drive mechanism of the type disclosed in U.S. Pat. No. 5,417,158, the disclosure of which is incorporated by reference herein in its entirety. 
   With reference to  FIGS. 2 , and  4 - 6 , the feeder head assembly  20  of the present invention preferably includes a generally cylindrical feeder head  22  in the form of a hollow drum. The feeder head  22  is supported at one end by a shaft  24 . The shaft may be attached to a drive system which causes the drum to reciprocally rotate between the first and second positions in a manner well known in the art. The other end of the housing includes an opening  26  which may be in communication with a vacuum source through a vacuum connector  28 . A hollow tube  29  extends from the connecter  28  to vacuum opening  26 . A sealing device (not shown) connects the tube  29  and the opening  26 , and a step  30  is formed on the end wall of the feeder head to accommodate such a seal. With further reference to  FIG. 3 , the feeder head assembly  20  is bounded by rotating rollers  32  (shown in  FIG. 2 ), which engage pinch rollers  33 . The rollers  32  and  33  move the printable material  14  from the feeder head assembly  20  through the feeder  12 . The generally cylindrical shape of the feeder head  22  is formed by the housing  34  and a removable cap  36 . The cap  36  is preferably the component of the device that comes in primary contact with the printable material  14 . In the present invention, the cap  36  can be removed from the housing  34  easily by an operator without removing any other component of the printing machine. The advantages of such a feature will be set forth more fully below. 
   Referring to  FIGS. 5 and 8 , the housing  34  includes a first end wall  38  preferably having a generally D-shaped configuration. This end wall is fixedly attached to the shaft  24  which may be press-fit into an opening formed in first end wall  38 . Extending outwardly from the first end wall  38  is a curved semi-tubular middle section  40  having a generally C-shaped cross-section. The middle section  40  terminates in a second wall  42  having a semi-circular aperture  44  therein. The housing  34  defines a longitudinally extending opening  46  which is covered by the cap  36 . The opening  46  is preferably a single uninterrupted opening. In the preferred embodiment, the opening  46  has a generally rectangular shape. The opening  46  is defined by a first end wall edge  48   a  and a second wall edge  48   b  and by a top  50   a  and bottom  50   b  edge of the middle section  40 . These edges together form a rim  52  on which sits the edges  54  bounding the perimeter of the cap  36 . It should be understood, within the contemplation of the present invention, that the inner edge of the rim  52  could have a different shape from that of the outer perimeter of the rim  52 . It should be also understood that the feeder head  22  and its housing  34  and cap  36  components could be made to form either more or less of the cylindrical drum, with the cap  36  designed to complete the generally cylindrical shape. The feeder head  22  is preferably formed of metal such as aluminum, although other material such as steel or plastic could be used. Also, it is understood that the housing  34  and cap  36  could be made from different materials, such as the housing  34  made of aluminum and the cap  36  made of plastic. 
   Referring additionally to  FIGS. 9 and 10 , the cap  36  is removably securable to the housing  34  over the opening  46 . The cap  36  is removable from the housing  34  in the generally radial direction as shown in  FIG. 5 . The cap  36  preferably has a generally arcuate profile, and when it is attached to the housing  34 , the feeder head  22  has a generally round cross-sectional profile. It is within the contemplation of the present invention, that the feeder head  22  could alternatively be formed in a number of different cross-sectional profile shapes, for example, square, rectangular, semi-circular, etc. Also, a sa further alternative, the feeder head  22  could have convex sides, (i.e., a barrel shape) or concave sides. As a further alternative, the housing  34  could form a portion of a generally cylindrical shape, while the cap  36  can have a different curvature or shape, or even just a portion thereof that has a different curvature or shape from the housing  34 . The profile of the feeder head  22  should be designed to achieve the desired level of material engagement and handling, in conjunction with the vacuum source. The cap has first  56  and second  58  end walls connected by a central curved section  60 . The first  56  and second  58  end walls and central section  60  define an inner hollow region or trough  62 . When the cap  36  is secured to the housing  34 , trough  62  along with the interior of the drum forms a vacuum chamber  64  ( FIG. 4 ). The central section  60  includes a material engagement surface  66  for engaging the printable material  14 . The engagement surface  66  has at least one aperture  68  to allow vacuum to be drawn there-through. In the preferred embodiment, the cap  36  includes a plurality of apertures  68  as shown in  FIG. 4 . In addition, it is within the contemplation of the present invention that the apertures  68  can be formed in a variety of shapes, e.g., round or slotted, and sizes, and a wide variety of aperture patterns may be used as shown in  FIGS. 9A to 9F . In addition, the configuration of the material engagement surface  66  may be varied depending on the nature of the printable material  14 . The engagement surface  66  may be rounded as shown in  FIGS. 9A to 9D . Alternatively, the material engagement surface may have a longitudinally extending flat  70  on it as shown in  FIGS. 7 ,  9 E and  9 F. Alternatively, the material engagement surface  66  may be formed in different shapes to accommodate the material that is being transferred. 
   The interior of the generally hollow housing  34  and the trough  62  formed in cap  36  create a relatively large vacuum chamber  64  at a location adjacent to the engagement surface  66  to which the printable material  14  is engaged. Such a volume of vacuum allows for compensation of leaks between the printable material  14  and the engagement surface  66  thereby permitting the vacuum level to remain generally constant throughout the act of transfer. 
   Referring specifically to  FIGS. 5 and 10 , the cap has a bottom side  72  that is bounded by the outer edge  54 . A plurality of spaced fastening holes  74  extend through the outer edge. The outer edge  54  is configured to sit on the rim  52  of the housing. Fasteners  76 , such as screws, may be used to removably secure the cap to the housing. Since the housing opening  46  extends underneath substantially the entire central section  60  of the cap, an aperture  68  formed anywhere on the central section  60  of the cap will be in communication with the vacuum chamber  64  formed within the interior of the drum  22 . Therefore, caps  36  having a variety of aperture configurations and patterns may be used on the same housing  34 . The configuration of the cap aperture(s) does not have to match the configuration of the drum opening. 
   The cap bottom side  72  may include a pair of longitudinally extending projections  78  disposed inward of the longitudinal extending edges of the cap. The projections  78  fit just within the housing opening  46  and help position the cap  36  on the housing  34 . 
   When the feeder head assembly  20  of the present invention is disposed within a feeder  12 , the cap  36  is accessible to an operator without removing other parts of the printing machine  10 . Therefore, the cap  36  can be unfastened from the housing  34  and easily replaced with another cap. The ability to change the cap permits for ease of configuring the machine to correspond to the material being printed and also permits for ease of routing maintenance. 
   In operation, printable material  14  is placed in a feeder  12  on top of the feeder head assembly  20  and more particularly the cap  36 . Vacuum is applied to the vacuum chamber  64  in the interior of the drum and to the apertures  68  in the cap  36 . A piece of printable material, such as an envelope, is sucked onto the cap by action of the vacuum ( FIG. 3 ). The shaft  24  and the feeder head  22  attached thereto are then rotated such that the envelope  14  is fed to pinch rollers  33  and carried by belts or chains to the printing station  16  in a manner well known in the art. The feeder head  22  is then rotated back to the initial position to engage another envelope  14 . The feeder head  22  may be reciprocated back and forth and a high rate of speed such that 40,000 to 80,000 envelopes an hour can be fed to the printing station  16 . 
   The cap  36  is in contact with the printable material, and this contact occurs at a very high speed. When the envelope  14  is transferred from the bottom of the stack to the pinch rollers  33 , the pinch rollers, in cooperation with rollers  32 , pull the envelope off the cap  36  while the envelope  14  is being held thereon by vacuum. Due to this type of action, caps  36  wear out over time, and it is a significant advantage to be able to quickly change them. In addition, depending on the nature of the printable material, different configurations and/or materials may be required. For example, if the printable material  14  to be fed is an envelope having a window, the window will come in contact with the cap  36 . If the cap engagement surface  66  is too rough, then the window may be scratched, thereby reducing the quality of the finished product. It has been found that using a cap  36  made of plastic reduces the incidence of scratching. However, the surface of the cap is subject to significant wear; therefore, it is preferable that the material be wear-resistant. As set forth in U.S. Pat. No. 5,417,158 a plastic made from ultrahigh molecular weight polyethylene (UHMWPE) provides a smooth, wear-resistant surface. Alternatively, if the envelope has no window and scratching of the surface is not an issue, then an aluminum cap can be used. It has been found that an aluminum surface coated with thermal spray-plasma molybdenum, or moly coat, provides a surface that is good for gripping paper material and is highly resistant to wear. It is within the contemplation of the present invention that to form cap  36  other materials or coating may be used depending upon the desired application. 
   In the present invention, the cap  36  may be removed when the feeder head is secured within the feeder of the printing press without the need to remove the entire transfer device from the machine. When the feeder head assembly is in the first position, the cap and the fasteners holding the cap to the drum are readily accessible to an operator as shown in  FIG. 2 . The operator needs simply to remove the fastening hardware  76 , lift the cap  36  off of the housing  34  in a generally radial direction, and put on and secure the replacement cap. Since the opening  46  in the housing  34  preferably extends under substantially the entire central section of the cap  60 , a cap having various aperture configurations can be used without removing the housing and the shaft attached thereto. 
   Although the illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention.