Abstract:
In one embodiment of the present invention, a sheet folding system is provided. The sheet folding system includes a first wall, a second wall coupled to the first wall, a third wall and a fourth wall coupled to the third wall. The walls are configurable in a first configuration in which a chamber adapted to receive a sheet is formed at least partly by the walls. The walls are also configurable in a second configuration in which the first and second walls are substantially coplanar, the third and fourth walls are substantially coplanar and the chamber is substantially collapsed. The sheet folding system can include a fastening device adapted to hold at least a portion of the sheet substantially in a desired position relative to the first wall. The sheet folding system can include a position indicator. The sheet can be a sheet of paper.

Description:
BACKGROUND 
   There is often the need to fold a flexible sheet of material. For example, millions of pieces of paper are folded each workday so that the paper is folded neatly and can be completely inserted into a standard sized envelope smaller than the piece of paper for mailing or for any of a number of other reasons. For some flexible sheets of material, such as paper, it is commonplace for the folding operation to be performed entirely manually. However, particularly when the sheet is paper or of similar thickness to paper, there is the danger of cutting oneself during the entirely manual folding process. 
   Partly to address the issue of paper-cuts and partly to increase the speed with which large amounts of folding can be accomplished, automatic folding devices, such as the ones described in U.S. Pat. Nos. 4,391,596; 5,094,658; 5,374,233; 5,876,320; 6,210,309 and 6,852,073, were developed. However, such automatic folding devices are complicated, having several moving parts, rollers, cylinders and/or plowshares. Typically, the complexity results in more opportunities for parts of the folding device to break or malfunction, leading to a system failure. Further, the complexity results in a device that is expensive to make. Even further, such folding devices operate on electrical power, making operating the devices an additional electrical expense when energy costs are high, and making operating the devices an impossibility when the power is out. 
   SUMMARY 
   In one embodiment of the present invention, a sheet folding system is provided. The sheet folding system includes a first wall, a second wall coupled to the first wall, a third wall and a fourth wall coupled to the third wall. The first, second, third and fourth walls are configurable in a first configuration in which a chamber adapted to receive a sheet is formed at least partly by the walls. The first, second, third and fourth walls are also configurable in a second configuration in which the first and second walls are substantially coplanar, the third and fourth walls are substantially coplanar and the chamber is substantially collapsed. 
   The sheet folding system can include a fastening device adapted to hold at least a portion of the sheet substantially in a desired position relative to the first wall. The sheet folding system can include a position indicator adapted to facilitate positioning the sheet in the chamber such that a portion of the sheet is in a desired location after the sheet is folded. The position indicator can be a transparent or translucent section of the first wall. The position indicator can be one or more marks on the first wall. 
   The sheet can be a sheet of paper. Also, the first wall can include a first segment and a second segment, wherein at least part of the first segment is adapted to be within the second segment in a first telescopic position and outside of the second segment in a second telescopic position. 
   In another embodiment, a sheet folding system is provided. The sheet folding system includes a plurality of walls. The walls are hingedly coupled together. Further, the walls are adapted to be arranged in a first configuration in which the walls at least partly define a chamber adapted to receive a sheet. The walls are also adapted to be arranged in a second configuration in which the chamber is substantially collapsed. 
   The sheet folding system can also include a fastening device adapted to hold at least a portion of the sheet substantially in a desired position relative to one of the walls. The sheet folding system can include a position indicator adapted to facilitate positioning the sheet in the chamber such that a portion of the sheet is in a desired location after the sheet is folded. The position indicator can be a transparent or translucent section of one of the walls. The position indicator can be one or more marks on one of the walls. 
   The sheet can be a sheet of paper. One of the walls can include a first segment and a second segment, wherein at least part of the first segment is adapted to be within the second segment in a first telescopic position and outside of the second segment in a second telescopic position. 
   The sheet folding system can include a force imparting device adapted to exert a force to return the force imparting device to a resting position. The force imparting device can be coupled to two of said plurality of walls. Further, the force imparting device can be in the resting position when said plurality of walls are in the first configuration. The force imparting device can be a hinge. 
   In another embodiment, a method of folding a sheet is provided. The method includes arranging the sheet in a chamber at least partly formed by a plurality of walls and collapsing the chamber. The sheet can be paper. The method can also include holding at least a first portion of the sheet to at least one of the plurality of walls so that a second portion of the sheet is in a desired position after the sheet is folded. The plurality of walls can include at least four walls. 
   Additional features and advantages are described herein, and will be apparent from, the following Detailed Description and the figures. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  is a flow diagram of the process of folding a flexible sheet in accordance with one embodiment of the present invention 
       FIG. 2  is a diagram of a sheet folding device in accordance with one embodiment of the present invention. 
       FIG. 3  is a diagram of the sheet folding device of  FIG. 2  with a sheet partly inserted. 
       FIG. 4  is a diagram of the sheet folding device of  FIG. 2  with a sheet fully inserted. 
       FIG. 5  is a diagram of the sheet folding device of  FIG. 2 , wherein the walls are repositioned to partly collapse the interior chamber. 
       FIG. 6  is a diagram of the sheet folding device of  FIG. 2 , wherein the walls are repositioned to collapse the interior chamber. 
       FIG. 7  is a diagram of the sheet folding device of  FIG. 2 , wherein the walls are returned to their original position. 
       FIG. 8  is a diagram of the sheet folding device of  FIG. 2  with the folded sheet partly removed. 
       FIG. 9  is a diagram of a sheet folding device with telescopic sides in accordance with one embodiment of the present invention. 
       FIG. 10  is a diagram of the sheet folding device of  FIG. 9 , wherein two sides are positioned to elongate the sheet folding device. 
       FIG. 11  is a diagram of a sheet folding device having a fastening device in accordance with one embodiment of the present invention. 
       FIG. 12  is a diagram of a side wall of the sheet folding device of  FIG. 12 . 
       FIG. 13  is a flow diagram of the process of folding one or more sheets of paper in accordance with one embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   In one embodiment of the present invention, a flexible sheet of material is folded by inserting the sheet into a chamber and collapsing the chamber.  FIG. 1  illustrates the process of folding a flexible sheet in accordance with one embodiment of the present invention. Preferably, the sheet is rolled into a tube-like shape before insertion into the chamber as shown at step  100 ; however, it is not necessary to roll the sheet before, during or after insertion into the chamber and the sheet can be placed in any suitable position and/or configuration within the chamber before the chamber is collapsed. Preferably, the sheet (e.g., paper) is arranged in the chamber such that when the sheet is folded, the fold or folds are perpendicular to at least one side of the sheet, resulting in a neatly folded sheet; however, the sheet can be arranged in the chamber in any suitable manner. 
   At step  110 , the chamber is collapsed, folding the sheet as a result. Preferably, the chamber is collapsed by manually imparting a force upon a side of the chamber; however, the chamber can be collapsed in any suitable manner. Preferably, when the chamber collapses, the interior walls of the chamber are rearranged into two substantially parallel walls of approximately equal length, thus folding portions of the sheet that overlapped in the plane of the parallel walls; however, the interior walls of the chamber can be arranged in any suitable manner upon collapse of the chamber. At step  120 , the folded sheet is removed from the chamber. 
   One embodiment is illustrated by  FIGS. 2-8 . The sheet folding device  200  preferably includes four side walls  202  orthogonally connected to define a chamber  204 . Preferably, the four side walls  202  each have the same lengths, widths and thicknesses; however, the four side walls  202  can have dimensions that differ from one or more of each other. Preferably, the top  206  and bottom  208  of the chamber  204  are uncovered, allowing materials to be inserted or removed from either the top  206  or bottom  208 ; however, either the top  206  or the bottom  208  can be closed, if desired, in any suitable manner including, but not limited to, positioning a suitable sized wall at the top  206  and/or bottom  208 , and coupling the wall to one of the four side walls  202  or to a coupling device that links two or more of the four side walls  202  to each other. 
   Further, the four side walls  202  are preferably hingedly connected, to enable the four side walls  202  to change their relative angles, resulting in the open top  206  and bottom  208  changing from a substantially square or rectangular shape to a substantially rhombus or parallelogram shape, and further resulting in the top  206  and bottom  208  becoming substantially a line as two of the four side walls  202  are arranged to form substantially one collinear wall  210  positioned substantially adjacent to another substantially one collinear wall  214  formed by the other two of the four side walls  202 ; however, the four side walls  202  can be connected in any suitable manner. The hinged connection of side walls  202  is preferably made by one or more hinges; however, the side walls  202  can be connected in any suitable manner. Preferably, the hinges have a spring-back or bend-back movement capability; however, any suitable hinge or combination of hinges can be used It should be noted that the terms top, bottom and side are used for convenience only and that the walls can be arranged in any suitable orientation relative to another object or an observer. 
   The four side walls  202  can be any type of material including, but not limited to, cardboard, plastic, wood, metal or a combination of any suitable materials. In one embodiment, the four side walls  202  are preferably approximately 2.36 inches or 6 cm wide and approximately 8.26 inches or 21 cm long; however, the four side walls  202  can have any suitable size and/or ratio of width to length. In one embodiment, the dimensions of the box-like structure formed by the four side walls  202  are determined by the desired maximum dimensions for a folded sheet. For example, the sheet to be folded  212  is preferably paper, but can be any suitable sheet of material, and the sheet  212  may be folded by the sheet folding device  200  for the purpose of then placing the preferably neatly folded sheet in an envelope (e.g., one of several standard sized envelopes). In such circumstances, it is desirable to have the box-like structure of such size that after folding the sheet  212 , the folded sheet is suitably sized for complete insertion into the envelope. Thus, the dimensions of the sheet folding device  200  may vary depending upon the desired envelope size. It should be noted that while folding of a single sheet  212  is discussed, multiple sheets can be folded in one collapse of the chamber  204 , if desired. Further, multiple sheets of differing sizes can be folded in one collapse of the chamber  204 . For example, two or more sheets of paper, at least two of which have different sizes, can be arranged together loosely or fastened together by a staple, paper clip, adhesive, static charge or other fastening device, placed in the chamber, and folded simultaneously and neatly as the chamber collapses, resulting in each of the sheets of paper being suitably folded for insertion into a standard sized envelope. 
   Accommodation of multiple sizes of envelopes is preferably accomplished by having two or more sheet folding devices  200  which are of different, fixed sizes. However, accommodation of multiple sizes of envelope can be accomplished in any suitable manner including, but not limited to, having one or more of the side walls  202  be of variable width and/or length.  FIGS. 9-10  illustrate a sheet folding device  300  having at least one variable width side wall  302 . The structure and operation of the sheet folding device  300  is similar to that of sheet folding device  200 ; however side walls  302  are telescopic. Preferably, a side wall is made telescopic by forming the wall of at least two members, an inside member  304  and an outside member  306 . A portion of the inside member  304  is positioned substantially inside of a portion of outside member  306 . When at a minimum width position as shown in  FIG. 9 , the maximal amount of inside member  304  is covered by outside member  306 . However, the two members can be repositioned, as shown in  FIG. 10 , preferably by sliding but any suitable manner of repositioning can be used, such that less of inside member  304  is enclosed by outside member  306 , resulting in a longer total width of the wall formed by the members. 
   Preferably, the two members are prevented from separating completely, however the two members can be separable, if desired. Preferably, when the two members are being repositioned, a user can identify the correct position for the desired envelope size. Preferably, the members have one or more stopping positions in which the members are more resistive of relative movement to both indicate the correct position for the desired envelope size (e.g., one of several standard envelope sizes) and/or to prevent the members from slipping out of the desired position; however, the user can identify the correct position by visual markers or in any other suitable manner. 
   The process of folding a sheet preferably begins with chamber  204  substantially vacant and sides walls  202  arranged substantially orthogonally, as shown in  FIG. 2 ; however, the chamber need not be vacant and the side walls  202  can be arranged in any suitable configuration. The sheet  212  is preferably rolled into a tube-like shape; however, the sheet can be arranged in any suitable configuration. Further, the sheet  212  can be folded together with one or more additional sheets or can be folded alone. The additional sheets can be rolled or otherwise configured loosely with the sheet  212  or the additional sheets can be secured to the sheet  212  with a staple, clip or in any other suitable manner. 
   The rolled sheet  212  is placed within the chamber  204 , as shown in  FIGS. 3-4 . The sheet folding device  200  is preferably oriented with the top side  206  up; however, the sheet folding device  200  can be arranged in any suitable manner. With the sheet  212  arranged in the chamber  204 , force is applied to at least one of the side walls  202 . The side walls  202  move through the configuration shown in  FIG. 5  to the configuration shown in  FIG. 6 . As a result, the chamber  204  collapses and the sheet  212  is folded. The side walls  202  are next moved back towards the original orthogonal position as shown in  FIG. 7 , and the folded sheet  212  can be removed from the sheet folding device  200  as shown in  FIG. 8 . 
     FIG. 11  illustrates an optional fastening device  400  used to hold at least a portion of the sheet to be folded in a desired location during the folding process. The fastening device  400  is illustrated as a single clip running along the top side of one of the side walls  402 ; however, the fastening device  400  can be a slot within the side wall  402  for receiving a portion of the sheet or any other suitable device or devices for holding at least a portion of the sheet in a desired location. Further, the fastening device  400  is illustrated as being non-removeably fixed to the side wall  402 ; however, the fastening device  400  can be removeably attached to the side wall  402 , if desired. 
   As shown in  FIG. 12 , the side wall  402  can include positioning indications  404  to assist with positioning the sheet within the chamber. Preferably, the side wall  402  is transparent or translucent, allowing the sheet to be viewed through the side wall  402 ; however, one or more portions of the side wall  402  can be transparent or translucent with other portions being opaque or the side wall can be entirely opaque or have any other suitable light transmitting properties. It should be noted that while the positioning indications  404  are shown in conjunction with the side wall  402  having a fastening device  400 , a fastening device  400  can be present without positioning indications  404  and positioning indications  404  can be present without a fastening device  400 . 
     FIG. 13  illustrates the process of folding one or more sheets of paper in accordance with one embodiment of the present invention. At step  1300 , the one or more sheets of papers are positioned in the folding device such that a portion of the outer most sheet, having address information, is aligned with positioning indicators. The indicators are configured such that when paper is folded in accordance with the indicators, the portion having the address information will be aligned with a transparent viewing window when inserted into the desired envelope. At step  1310 , a portion of the paper is held to one of the sides of the folding device by a fastening device. The portion is held so that the paper does not slip out of alignment with the positioning indicators during folding. 
   At step  1320 , a force is applied to at least one of the sides of the sheet folding device. At step  1330 , the sides of the sheet folding device reposition, causing the interior chamber holding the paper to collapse and consequently fold the paper. At step  1340 , the sides return at least part way to their original configuration. The sides preferably return at least part way to their original configuration because at least one of the hinges provides enough force one the collapsing force is removed to cause the sides to move; however, the sides can move due to manually applied force or due to any other suitable cause. At step  1350 , the folded paper is released from the fastening device, and at step  1360 , the folded paper is removed from the sheet folding device. The folded paper is then ready for insertion into an envelope such that the address on the paper is viewable from the transparent or translucent window of the envelope when the folded paper is completely inserted. 
   It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.