Abstract:
A cushioning conversion machine for converting sheet-like stock material into a relatively low density cushioning dunnage product. The machine has at least one conversion assembly for forming the stock material into a three-dimensional shape. The machine includes a feed mechanism for drawing the stock material over a shaping member in the conversion assembly. Any one of a plurality of manually operated severing mechanisms can be mounted in the second unit for cutting the cushioning dunnage product into cut sections. One severing unit has a circular cutting disc which is driven by a rack and pinion faster than rolling contact along a reaction member. Another severing mechanism has a fixed blade with an inclined cutting edge that moves across the path of the converted material. A third mechanism has straight edged blade that moves on vertical tracks downward through the path of the emerging converted material to sever the material against a fixed reaction member. Another mechanism has a taught wire which can be pulled through the converted material. A reaction bar with a slot is located on one side of the path of the material and the wire is pulled up through the slot, trapping and then severing the material. In another mechanism, a pair of blades with serrated edges are mounted for vertical movement in a plane transverse to the path of the converted material, the blades are driven in a reciprocating motion a by a pair of out of phase zigzag cams and a cam follower attached to each of the blades.

Description:
FIELD OF THE INVENTION 
     The invention herein described relates generally to cushioning conversion machines and more particularly to improvements in the mechanisms for cutting cushioning materials formed by such machines. 
     BACKGROUND OF THE INVENTION 
     In the process of shipping an item from one location to another, protective packaging material is often placed in the shipping container to fill any voids and/or to cushion the item during the shipping process. Some commonly used protective packaging materials are plastic foam peanuts and plastic bubble pack. While these conventional plastic materials seem to perform adequately as cushioning products, they are not without disadvantages. Perhaps the most serious drawback of plastic bubble wrap and plastic foam peanuts is their effect on our environment. Quite simply, these plastic packaging materials are not biodegradable, and therefore they cannot avoid further multiplying our planet&#39;s already critical waste disposal problems. The non-biodegradability of these packaging materials has become increasingly important in light of many industries adopting more progressive policies in terms of environmental responsibility. 
     The foregoing and other disadvantages of conventional plastic packaging materials have made paper protective packaging material a very popular alternative. Paper is biodegradable, recyclable and composed of a renewable resource; making it an environmentally responsible choice for conscientious shippers. 
     While paper in sheet form could possibly be used as a protective packaging material, it is usually preferable to convert the sheets of paper into a relatively low density pad-like cushioning or dunnage product. This conversion may be accomplished by a cushioning conversion machine, such as that disclosed in commonly assigned U.S. Pat. No. 5,123,889. The conversion machine disclosed in U.S. Pat. No. 5,123,889 converts sheet-like stock material, such as paper in multiply form, into relatively low density pads. Specifically, the machine converts this stock material into a continuous unconnected strip having lateral pillow-like portions separated by a thin central band. This strip is coined along its central band to form a coined strip which is cut into sections, or pads, of a desired length. The stock material preferably consists of three superimposed webs or layers of biodegradable, recyclable and reusable thirty-pound Kraft paper rolled onto a hollow cylindrical tube. A thirty-inch wide roll of this paper, which is approximately 450 feet long, weighs about 35 pounds and will provide cushioning equal to approximately sixty cubic feet of plastic foam peanuts while at the same time requiring less than one-thirtieth the storage space. 
     The converting machines known in the prior art, including the one shown in U.S. Pat. No. 5,123,889, have utilized a guillotine type cutter to sever the coined strip into sections of the desired length. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved cutter mechanism for cushioning conversion machine which is able to sever a converted strip of cushioning in an efficient and effective manner. In one embodiment of the present invention the cutting mechanism includes a rotating, circular blade mounted for movement along a track which is transverse to the path of the converted strip of cushioning through the machine. The blade preferably is driven by an attached gear which engages a fixed rack. As the blade traverses the paper path, the cutting edge turns faster than rolling contact, causing a severing action. 
     In a second embodiment, the cutting mechanism includes a knife mounted for movement along a track which is transverse to the path of the converted strip of cushioning though the machine. The cutting edge of the knife is slanted, and the tip of the blade rides in a slot which is parallel to and below the track. As the knife is drawn across the paper, the sharp edge presses the paper downward toward the slot until there is enough pressure to force the knife through the paper severing the strip into sections of the desired length. 
     In a third embodiment, a wire is positioned below the path of the converted strip of cushioning through the machine. A shearing bar which includes a lengthwise slot is positioned above the path of the converted strip of cushioning through the machine. The wire can be lifted through the slot by a pair of hooks which extend through the slot and straddle the strip. When first one hook and then the other are lifted, the sharp, thin wire shears the paper as the wire passes through the slot. 
     In a fourth embodiment, the cutting mechanism includes an opposed pair of knife edges, one of which is mounted for vertical movement across the path of the strip of converted paper through the machine, and the other of which is fixed below the path of the strip. A lever, crank and connecting rod actuate the moveable knife edge and bring it into forceful contact with the fixed blade to sever the strip of paper. 
     In a fifth embodiment, the cutting mechanism includes a pair of serrated blades mounted side-by-side. The blades are movable along vertical tracks located on opposite sides of the path of the converted strip through the machine. Each track also includes a zigzag cam which engages and drives a cam follower connected with one of the blades. The cams are positioned so that the blades oscillate with respect to each other as they move downward through the converted strip. 
     These cutting mechanisms are used as part of a cushioning conversion machine which converts sheet-like material into a relatively low density cushioning dunnage product. A preferred machine comprises initial and subsequent units having separate housings. The initial unit includes in the housing thereof a shaping member over which the sheet-like stock material is drawn to form the stock material into a three-dimensional shape. The subsequent unit includes in the housing thereof a feed mechanism for drawing the stock material over the shaping member of the initial unit. The housings of the initial and subsequent units respectively have an outlet opening and an inlet opening relatively positionable with respect to one another to provide a pathway for transfer of the sheet-like material from the initial unit to the subsequent unit. The cutting mechanism is mounted in the subsequent unit for cutting the cushioning dunnage product into cut sections. 
     The present invention provides the foregoing and other features hereinafter fully described and particularly pointed out in the claims, the following description and annexed drawings setting forth in detail certain illustrative embodiments of the invention, these embodiments being indicative, however, of but a few of the various ways in which the principles of the invention may be employed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a cushioning dunnage conversion machine constructed in accordance with the teachings of U.S. patent application Ser. No. 08/486,811. 
     FIG. 2 is a side elevational view of a first embodiment of the present invention showing a circular blade mounted for movement along a track which is transverse to the path of the converted strip of cushioning through the machine; 
     FIG. 3 is a cross-sectional view taken along the line  3 — 3  of FIG. 2; 
     FIG. 4 is a cross-sectional view taken along the line  4 — 4  of FIG. 3; 
     FIG. 4A is a simplified partial view of a portion of FIG. 4, showing an alternative mounting of the severing member  130 ;. 
     FIG. 5 is an end view transverse to the strip path through the machine showing a second embodiment of the present invention; 
     FIG. 5A is an end view of an alternative severing member for the second embodiment of the present invention; 
     FIG. 6 is a cross-sectional view taken along the line  6 — 6  of FIG. 5; 
     FIG. 7 is an end view transverse to the strip path through the machine and showing a third embodiment of the present invention; 
     FIG. 8 is a cross-sectional view taken along the line  8 — 8  of FIG. 7; 
     FIG. 9 is a view looking in the direction of arrows  9 — 9  of FIG. 7; 
     FIG. 10 is a view generally similar to FIG. 7, but showing a severing member partway through a severing process; 
     FIG. 11 is a view similar to FIG. 10 but showing the severing member after completing the severing process; 
     FIG. 12 is a cross-sectional view looking in a direction transverse to the path of the strip through the machine and showing a fourth embodiment of the present invention; 
     FIG. 13 is a cross-sectional view taken along the line  13 — 13  of FIG. 12; 
     FIG. 14 is a view similar to FIG. 13 but showing the severing member at the completion of its severing stroke; 
     FIG. 15 is a cross-sectional view transverse to the strip path through the machine and showing a fifth embodiment of the present invention; 
     FIG. 16 is a cross-sectional view taken along the line  16 — 16  of FIG. 15; 
     FIG. 17 is a view generally similar to FIG. 15 but showing the severing members at the completion of their severing stroke; 
     FIG. 18 is a cross-sectional view taken along the line  18 — 18  of FIG. 16; 
     FIG. 19 is a view looking in the direction of arrows  19 — 19  of FIG.  18 . 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a cushioning conversion machine  30  constructed in accordance with U.S. patent application Ser. No. 08/486,811. The conversion machine  30  includes a stock supply assembly  32 , a forming assembly  34 , and a feed/connecting and cut-off assembly  36 , the latter hereinafter also being more simply referred to as the feed and cut assembly. In the illustrated machine, the stock supply assembly  32  and forming assembly  34  are associated with a former unit  38  while the feed/connecting and cut-off assembly are associated with a head unit  40 , this being similar to the arrangement described in U.S. patent application Ser. No. 08/486,811, which is hereby incorporated herein by reference in its entirety. 
     In use, the conversion machine  30  processes sheet-like stock material to form dunnage which may be used for packing or shipping purposes. The sheet material may consist of two, three, or more superimposed plies or layers of biodegradable, recyclable, and reusable paper, for example 30 or 50 pound Kraft paper, which may be supplied in a roll  44  or otherwise. The illustrated conversion machine  30  converts this stock sheet material into a continuous strip of cushioning with lateral pillow-like portions separated by a thin central band. This strip is “connected” as by coining along the central band and may be cut into sections of a desired length. 
     The stock supply assembly  32  may include a constant entry roller  48  and various bars or rollers  50 ,  52 , and  54  for separating the layers of sheet material before being fed into the forming assembly  34 . The stock supply assembly  32  may also include a holder  56  which may support a roll of sheet material. Alternatively, the sheet material may be fed directly to the roller  48  from a separate stand holding the sheet material, or by other suitable means. 
     The forming assembly  34  is similar to that shown in the aforesaid U.S. patent application Ser. No. 08/486,811. As the sheet material passes through the forming assembly  34 , it is formed into a continuous unconnected strip. While the forming assembly  34  is preferably like that shown in the above-mentioned U.S. patent application Ser. No. 08/486,811, other forming assemblies are also usable in the practice of the present invention. Reference also may be had to said application for further details of the illustrated former unit  38 . 
     The head unit  40  includes a frame  60  to which the various components of the feed and cut assembly  36  are mounted. The head unit preferably has an outer casing or shell  62  enclosing the various components of the feed and cut assembly. The former unit may be connected to the head unit in the manner illustrated in the aforesaid &#39; 811  application. 
     The feed and cut assembly  36  includes a motor  66  fastened to the frame  60 . The shaft of the motor  66  drives an output sprocket  68 . The sprocket  68  drives a chain  70  which in turn drives sprocket  72 . The sprocket  72  in turn is mounted to a shaft  74  which carries an upper coining gear  76 . The upper coining gear  76  is in constant mesh with a lower coining gear  78 . When the strip of paper exits the forming assembly  34 , it passes between the upper and lower coining gears  76  and  78  which secure a centrally located axially extending portion of the strip to hold it together, all in a manner well known in the art. 
     The feed and cut assembly  36  further includes a severing mechanism  80  to sever the emerging dunnage into strips of the desired length. The severing mechanism  80  is controlled by a manually operated handle  82  which is connected through a linkage to a vertically movable blade  84 . When the handle  82  is pulled downward and to the right (clockwise as viewed in FIG.  1 ), the blade  84  moves downward across the path  86  of the converted sheet material to sever the emerging strip at the desired location. The handle may also be used to control the feeding of stock material through the machine as in the manner described in the &#39; 811  application. 
     The present invention provides additional severing mechanisms, including the severing mechanism  100  illustrated in FIGS. 2-4. The severing mechanism  100  includes upper and lower horizontal frame members  102  and  104 , respectively, which extend laterally between the vertical side frame plates  106  of the frame  60 . The frame members  102  and  104  (which also form a part of the frame  60 ) are parallel to each other and spaced above and below the path of the converted sheet material. A vertical frame element  108  extends between the upper and lower frame members  102  and  104  and between the two side plates  106 , the vertical frame element being mutually perpendicular to all of these. The vertical frame element includes a rectangular opening  110  through which the converted sheet material passes. 
     The severing mechanism  100  includes a rod  112  which extends between the two side brackets  107  parallel to the vertical frame element  108  and just downstream of the opening  110 . A carriage  114  is mounted on the rod and is slidable along the rod in a direction transverse to the path of the converted sheet material, the rod functioning as a guide track and support for the carriage. The carriage  114  includes bearings  116  and  118  which allow it to slide easily on the rod  112 . The carriage also includes a handle  120  which is mounted on the top of the carriage  114 . The handle  120  may have the illustrated T-shape, with the stem thereof extending through a slot  122  in the upper horizontal frame member  102  and a corresponding, aligned slot  124  in the outer casing  62 . 
     The carriage  114  also includes a pair of downwardly extending side plates  126  and  128 . These side plates provide a mounting point for the circular severing member  130 . The circular severing member  130 , for example a cutting wheel, is rotatably mounted on a shaft  132  that extends between the side plates  126  and  128 . The severing member  130  has a sharp, peripheral edge  134  that bears against a planar support surface on a fixed angle  136  which is mounted to the vertical frame element  108 . The fixed angle  136  is parallel to the rod  112 , and so the edge  134  is in contact with the fixed angle, regardless of where along the rod the carriage  114  happens to be. (See FIG.  4 ). Alternatively, the fixed angle  136  may be mounted so that the edge  134  contacts the vertical surface of the angle  136  regardless of where along the rod the carriage  114  happens to be. (See FIG. 4A.) 
     The severing member  130  is driven to rotate about the shaft  132  by means of a spur gear  140  which cooperates with a rack  142 . The gear  140  is fixed to the shaft  132  as is the severing member  130 . The rack  142  is parallel to the rod  112  and extends between and is mounted to the side brackets  107 . When the handle  120  is used to move carriage  114  across the rod, the gear and rack  140  and  142  drive the severing member  130  so that its edge  134  has a greater velocity than the carriage  114  with respect to the fixed angle  136 . This action severs the converted sheet material into a strip of the desired length. Limit switches  150  may be provided to activate the feed motor  66 . 
     The present invention further provides the severing mechanism  200  illustrated in FIGS. 5 and 6. Where structural elements are identical to the elements in earlier described embodiments, identical reference numerals have been used. Where structural elements are similar to corresponding elements in previously described embodiments, the same reference numerals are used with a prime (′) added. This same convention is used throughout this application. 
     The severing mechanism  200  includes a severing member  130 ′ mounted to the carriage  114 ′. The severing member  130 ′ is in the form of a thin blade mounted for lateral movement in a plane perpendicular to the path of the converted strip of cushioning. The severing member  130 ′ is formed with a sharp severing or knife edge  202  which is inclined relative to the movement direction of the severing member. As illustrated, the edge  202  is at about a 45 degree angle to the guide rod  112 . (See FIG. 5.) Alternatively, the severing member  130 ′ may be formed with two knife edges inclined in opposite directions. (See FIG. 5A.) 
     The severing mechanism  200  also includes a blade guide or track  204 . The blade guide  204  is mounted to the lower horizontal frame member  104 , and it has a guide slot  206  which extends parallel to and directly below the rod  112 . The slot  206  receives the lowermost tip of the severing member  130 ′ and maintains the severing member in alignment with the rod  112 . 
     The blade guide  204  has a top surface  208  which is flush with the bottom of the opening  110  through the vertical frame element  108 . When the handle  120  is used to push the carriage  114 ′ across the rod  12 , the inclined edge  202  of the severing member  130 ′ squeezes the converted sheet material against the top surface  208  which forms a reaction surface for the severing member  130 ′. The converted sheet material is severed through by the combined effect of the inclined sharp edge  202  and the reaction surface  208  of the guide track  204 . If the severing member of FIG. 5A is used, it will cut in both directions thereby making alternative cuts in both directions. One or more limit switches  150 ′ may be provided to activate the feed motor  66 . 
     The present invention further provides the severing mechanism  300  illustrated in FIGS. 7-11. The severing mechanism  300  includes a support member  302  which is connected to the vertical frame element  108 . The support member  302  has a slot  304  which extends transverse to and above the path of the converted sheet material through the opening  110 . As will be seen from the following description, the support member also includes a lower, horizontal surface  306  to which the slot  304  opens and which forms a reaction surface for the severing operation. 
     The severing member  130 ″ takes the form of a thin wire such as piano wire. Alternatively or additionally, the wire  130 ″ may be coated with an abrasive. In either event, the wire  130 ″ is secured at one end  308  to the lower horizontal frame member  104  by any suitable means. The opposite end  310  of the wire  130 ″ is connected to a stiff coil spring  311  which is in turn mounted at  312  to the horizontal frame member  104 . The mounting points  308  and  312  are on opposite sides of the opening  110  through the vertical frame element. As a result the wire  130 ″ in its initial position is stretched taught below the path of the converted sheet material. 
     The severing mechanism  300  further includes a pair of hooks  316  and  318  which serve to lift the wire  130 ″ to effect the severing operation. The hooks  316  and  318  are vertically moveable through holes  320  and  322 , respectively, through the upper horizontal frame member  102 ″. Each of the hooks  316  and  318  has a large loop  324  at its top to permit the hook to be gripped and lifted. The hooks  316  and  318  also each have a loop  328  at their lower ends through which the wire  130 ″ passes. In addition each of the hooks  316  and  318  includes a collar  330  to limit upward travel of the hooks. To accommodate the collars  330 , the slot  304  includes enlarged areas  332  (FIG. 9) through which the collars can pass. 
     To sever a desired length of converted sheet material, the hooks  316  and  318  are sequentially or simultaneously lifted to pull the wire  130 ″ through the sheet material. For example, the hook  316  can be lifted first as shown in FIG.  10 . The spring  311  stretches some as the wire  130 ″ moves upward. The collar  330  is positioned so that the wire  130 ″ passes through the slot  304  in the support member  302  before the collar hits the underside of the upper frame member  102 ″. As this occurs a nip  334  is formed between the bottom  306  of the support member  302  which squeezes the converted sheet material and severs it. Next the other hook  318  is lifted upward. As shown in FIG. 11, this finishes the squeezing and severing operation as the converted sheet material is forced upward against the support member  302  and the vertical side  336  of the opening  110  through the vertical frame element  108 . Alternatively, the wire  130 ″ may be initially tensioned and then released to sever the desired length of converted sheet material. 
     The present invention further provides the severing mechanism  400  illustrated in FIGS. 12-14. The severing mechanism  400  includes a vertically movable severing element  130 ′″ in the form of a knife blade which has a sharp lower edge  402 . The lower edge  402  is initially positioned above the path of the converted sheet material and can be moved downward to engage a fixed opposing knife edge  404  to effect the severing operation. 
     The severing mechanism  400  further includes a pair of side plates  406  and  408  which are generally vertical and extend between the upper and lower horizontal frame members  102  and  104  and which have an upstream edge abutting the vertical frame element  108 ′. The side plates  406  and  408  are positioned on opposite sides of the opening  110  through the vertical frame element  108 ′. Each of the side plates  406  and  408  includes a guide slot  412  and  414 , respectively (FIGS.  12  and  13 ), which guide the movement of the severing member or blade  130 ′″. 
     The blade  130 ′″ is generally rectangular, and its lower edge  402  is generally straight and horizontal. The blade  130 ′″ is supported by a pair of mounting blocks  416  and  418  which are mounted to the upper corners of the blade. Each of the mounting blocks has a pair of vertically aligned pins  420  and  422  which extend laterally from the block and are received in the respective slots  412  and  414 . The pins assure that the blade  130 ′″ moves in the straight line defined by the slots  412  and  414 . The lower pins  422  extend only far enough to reach into but not completely through the slots  412  and  414 . The upper pins,  420 , on the other hand, extend all the way through the respective slots  412  and  414  and laterally outwardly beyond the side plates  406  and  408  to provide a mounting point for a linkage  424  which drives the blade  130 ′″ up and down. 
     The linkage  424  includes a U-shaped handle  426  which spans the width of the head unit  40  in the same manner as the handle  82  shown in FIG.  1 . The handle  426  (FIGS. 12-14) is rotatably mounted by stub shafts  428  and  430  which are rotatably mounted in the side frames  106 ′″. The outer ends of the shafts  428  and  430  are connected to the handle  426 , while the inner end of each shaft is connected to a crank arm  432  and  434 , respectively. The crank arms  432  and  434  each have a pinned connection to one end of a respective connecting rod  440  and  442 , respectively. The opposite ends of the connecting rods  440  and  442  are pivotally connected to the pins  420  which drive the blade  130 ′″. 
     The blade  130 ′″ is initially in the position shown in FIGS. 12 and 13, and the converted sheet material is free to pass through the opening  110  with the lower edge  402  of the blade  130 ′″ above the path of the sheet material and the fixed knife edge  404  below. Once the desired length of cushioning has been produced, the feed motor is deactivated (either manually or automatically) and the handle  426  is pulled down (clockwise as viewed in FIGS.  13  and  14 ). This brings the edges  402  and  404  into contact through the operation of the linkage  424 , and so severs the material. 
     The present invention further provides the severing mechanism  500  illustrated in FIGS. 15-19. The severing mechanism includes a pair of oscillating serrated blades  502  and  504  (FIGS. 15 and 18) which form the severing member. The blades  502  and  504  move downward across the opening  110  (FIG. 15) through which the converted sheet material passes, and the oscillating motion of the blades severs the material as desired by the operator. 
     The mechanism  500  further includes two sets of vertical guide assemblies  506  and  508  which extend between the upper and lower horizontal frame members  102  and  104 . Each set of vertical guide assemblies is formed from two flat plates  510  and  512  shown in FIG.  18 . The two plates  510  and  512  are set with their major side surfaces facing each other and spaced apart by the combined thickness of the blades  502  and  504 . The plates  510  and  512  assure that the blades  502  and  504  can move vertically, but cannot twist, so that the serrated bottom edges of the blades are always facing down. 
     The blades  502  and  504  are driven vertically by a linkage mechanism  518  (FIG.  16 ). The linkage  518  includes a U-shaped handle  520  which spans the width of the head unit  40  in the same manner as the handle  82  shown in FIG.  1 . The handle  520  is rotatably mounted by stub shafts  528  and  530  which are rotatably mounted in the side frames  60 ″″ and  106 ″″. The outer ends of the shafts  528  and  530  are connected to the handle  520 , while the inner end of each shaft is connected to a crank arm  532  and  534 , respectively. The crank arms  532  and  534  each have a slot  542  and  544 , respectively, which engages and drives a follower assembly  546  and  548 , respectively, one of which is connected to each lateral end of the blades  502  and  504 . 
     The follower assemblies  546  and  548  (FIG. 18) each include a follower  550  and  552  which fit in the slot  542  and  544  of each crank arm  532  and  534 , respectively. A U-shaped bracket  554  and  556  is connected to the respective follower and it straddles the two blades  502  and  504 . Each of the blades  502  and  504  includes a horizontally extending slot  560  (FIG. 19) so that the blades can oscillate laterally with respect to the follower assemblies. The two follower assemblies may also be connected to each other by a stiffening rib  562  (FIGS. 15,  17  and  19 ), which assures that the axes of the followers  550  and  552  are the same. The stiffening rib  562  is narrower than the combined thickness of the blades  502  and  504  and centered above them. 
     The blades  502  and  504  are initially in the position shown in FIGS. 15 and 16, and the converted sheet material is free to pass through the opening  110  with the serrated lower edges of the blades above the path of the sheet material. Once the desired length of material has been converted, the handle  520  is pulled down (clockwise as viewed in FIG.  16 ). This brings the blades  502  and  504  downward through the operation of the linkage  518 . 
     The guide bars  570  and  572  of the set  508  each have a zigzag slot  574  (FIG.  19 ). The slot  574  receives a cam follower in the form of a pin  576  which is secured to the blade  504 . The slot  574  extends from above the top of the opening  110  to about even with the bottom of it. The slot  578  in the guide bar  572  is like the slot  574  but 180 degrees out of phase; the slot  578  zigs where the slot  574  zags and vice versa. The blade  502  also carries a follower pin  580  which fits in the slot  578 . 
     Each of the follower assemblies  546  and  548  includes a pin  582  and  584 , respectively, which passes through the slots  560  in the ends of the blades  502  and  504 . When the follower assemblies  546  and  548  push down on the blades  502  and  504 , the blades move downward, and the follower pins  576  and  589  track along in the respective slots  574  and  578 , causing the blades  502  and  504  to oscillate laterally as they descend through the converted sheet material to sever the material at the desired location.