Abstract:
A machine for producing folds in different media. The machine includes a pair of table top plates moveable relative to one another and define an escapement plate and the other a pleater plate. The plates grip the media at space apart locations approximately twice the distance of the required pleat heigth and as they cone together a pleat or fold is produced between the two plates. The escapement plate then rises allowing the pleat to move out beyond the return path of the escapement plate as it falls and clamps the media against the table top surface. When it reaches the bottom the pleater plate rises slightly to clear the media on the table surface and then moves away from the escapement plate to a position again approximately twice the pleat heigth in preparation of then gripping the web and moving forwardly toward the escapement plate to form the next fold or pleat. The pair of plates are moved along predetermined paths in timed relation by a pair of linkage systems. A power unit is connected to the respective linkage systems by a respective one of a pair of pneumatic piston-cylinder units the valving of which is capable of being controlled by a central processing unit to control the acceleration and deceleration of the moving plates and also when required have the piston-cylinder units act as a lost-motion connection between the driver and the driven plates.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Technical Field  
           [0002]    This invention relates generally to a machine for producing folds in a media and more particularly to a powered push/pull pleater. The machine is particularly designed to pleat a web, also referred to herein as a ribbon or strip, of material, such as a web of filter material particularly for air filters.  
           [0003]    2. Description of the Prior Art  
           [0004]    It is known to obtain pleated and/or chevron-patterned structures from single and multilayer sheet material by providing or forming crease lines on the sheet at the locations of the pleats and/or chevrons and thereafter causing the sheet to pass between two master-sheet formers. This method has the disadvantage of being slow and it is difficult to produce pleats of different amplitudes.  
           [0005]    In the above mentioned method, the means which support the forming heads are heavy and the inertia of the different parts prevents the mechanisms from being driven at high speeds thereby necessarily limiting the output of each machine.  
           [0006]    Other techniques have been developed for forming, from a continuously unwinding strips or webs, pleated and/or chevron-patterned structures, which techniques involve marking pleat and/or chevron creases on the flat web and, by simultaneously thrusting and guiding the web along a path which accentuates the formation of the pleats or chevrons as the case maybe. The major disadvantage of this stems from the complexity of the mechanisms needed to guide the web so that the ultimate structure assumes its pleated pattern without the creation of any appreciable tension capable of tearing the material or locally deforming the structure.  
           [0007]    Existing machines use power cylinder units that lack acceleration and deceleration control making them noisy and self destructive. Furthermore they do not have the ability to vary the amplitude of the pleat along with the ability to control the acceleration and deceleration of the movable pleat forming mechanisms.  
         SUMMARY OF THE INVENTION  
         [0008]    In one aspect of the present invention there is provided a pleater having a harmonic motion drive to power the pleater and escapement plates.  
           [0009]    The present invention provides a machine for pleating a ribbon of material. The pleater includes a rigid frame structure having an elongate flat surface and a first and second pair of plates having first and second respective surfaces disposed in face-to-face relation. Means is provided for mounting and guiding the first plate on the frame for reciprocal movement in a direction toward and away from the second plate along a predetermined path generally parallel to the flat surface. The means for mounting and guiding the second plate along a predetermined path in a direction toward and away from the flat surface is defined as well. A first and second drive linkage means is connected respectively to the first and second plates for moving the same along their respective predetermined paths. First and second push-pull members are connected respectively to the first and second linkage means. Each one comprises a piston-cylinder unit drivingly connected at one end thereof to the linkage means associated therewith to move the same and the other end is drivingly connectable to a suitable power means for reciprocating the same. Means on the first plate at a position closely adjacent to the flat surface can be utilized to releasably grip the ribbon transversely of length thereof. Moreover in a preferred embodiment, a lower edge of the second plate is moveable in a direction toward and away from the flat surface to selectively grip the ribbon therebetween.  
           [0010]    The pleating machine of the preferred embodiment provides an apparatus for continuously forming pleats one after another in a ribbon of material. A preferred embodiment includes a rigid frame structure having an elongate flat surface and a first and second pair of plates having first and second respective surfaces disposed in face-to-face relation. Means are included for mounting and guiding the first plate on the frame for reciprocal movement in a direction toward and away from the second plate along a predetermined path generally parallel to the flat surface. Means for mounting and guiding the second plate along a predetermined path in a direction toward and away from the flat surface are included together with means associated with the first and second plates for grippingly engaging a ribbon of material on the flat surface during movement of the first plate in a direction toward the second plate. A first and second drive linkage means is connected respectively to the first and second plates for moving the same along their respective predetermined paths. Power means drivingly connected to the linkages move the first and second plates in timed interrelated relation to form pleats one after another in the ribbon of material.  
           [0011]    It is an object of the present invention to provide a pleater that is compact, smooth in operation and can operate with quick cycle times for long periods of time.  
           [0012]    In accordance with one aspect of the present invention there is provided a pleater with a single drive for the pleater and escapement plates. The use of a single power source e.g. a motor gear box arrangement permits coordinating the two motions to optimize the mechanics of the pleating action.  
           [0013]    In accordance with a further aspect of the present invention, there is provided a method of pleating a material comprising the steps of drawing the material along a predetermined generally horizontal path. Pleats are formed therein by a pair of pleat forming plates that are moveable relative to one another, and a fixed structure defining the horizontal path, (or if selected a vertical path). Material is gripped by the plates at a pair of positions spaced apart from one another longitudinally along the strip of material, moving the plates relative to one another and the fixed structure to bring the plates together while maintaining the grip on the material and thereby forming a pleat. The plates are raised higher than the newly formed pleats disposed at a higher elevation than the strip of material in the predetermined path and repositioned for repeating the sequence to form a plurality of pleats.  
           [0014]    Applicants pleating machine is capable of producing folds in various different media and includes a pair of relatively movable plates that grip the media and then produce a fold or pleat as they come together. One of the plates known as the escapement plate moves upwardly and downwardly sufficiently to allow the new the new fold to move out past the return path of the downwardly moving escapement plate which also clamps the media. When the other plate, known as a pleater plate reaches the bottom of the stroke, it then raises slightly to move over the media, moves away from the escapement plate in a direction upstream toward a supply of the media to be pleated approximately twice the distance of the required pleat height and clamps the media again. The pleater plate grips the web and then moves toward the escapement plate again to form another pleat in the media as they close i.e. are moved together. The linkage and drive system of the pleater is capable of producing fast repetitive cycles.  
           [0015]    The pleating machine in accordance with an aspect of the present invention has drive linkages with lost motion connections provided by pneumatic cylinders. Computer control of the lost motion connections permits controlling the acceleration and deceleration of the movable pleating mechanisms as well as the ability to skip strokes and adjust the lenth of the link  415  when required to do so. The length of the stroke is changed by mechanically varying the sliding pivots  305 A on  305  or optionally by a central process unit. The slidable pivots are controlled by a central processing unit suitably programed to provide the requisite motions including skipping strokes at selected intervals (alternating intervals). The length of  415  is set automatically according to the length of the stroke providing harmonic motion.  
           [0016]    A principal object of the present invention is to provide for nonstop in-process formation and accentuation of the pleating, or formation and accentuation of the chevron pattern, on continuously supplied strip material, and thereafter withdrawal of the ultimate structure which maybe merely pleated or be both pleated and chevron patterned.  
           [0017]    It is another object to provide a machine for pleating paper, filter material, film coated paper, paperboard, and/or even corrugated material.  
           [0018]    Other objects, features and advantages of the invention will become apparent with the following detailed description taken in conjunction with the accompanying drawings showing a preferred embodiment of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings in which like numerals refer to like parts throughout the several views and wherein:  
         [0020]    [0020]FIG. 1 is an oblique view of a pleating machine provided in accordance with the present invention and looking in an upstream direction toward the material supply end thereof;  
         [0021]    [0021]FIG. 2 is similar to FIG. 1 but looking in the downstream direction with reference to the direction of travel of the web of material being pleated;  
         [0022]    [0022]FIG. 3 is an oblique view taken from the side of the machine opposite to that of FIGS. 1 and 2;  
         [0023]    [0023]FIG. 4 is a side view of the pleat forming movable plates in one position thereof;  
         [0024]    [0024]FIG. 5 is similar to FIG. 4 and shows one of the various different relative positions of the pleat forming movable plates;  
         [0025]    [0025]FIG. 6 is similar to FIG. 4 and shows various different relative positions of the pleat forming movable plates;  
         [0026]    [0026]FIG. 7 is similar to FIG. 4 and shows various different relative positions of the pleat forming movable plates;  
         [0027]    [0027]FIG. 8 is similar to FIG. 4 and shows various different relative positions of the pleat forming movable plates; and  
         [0028]    [0028]FIG. 9 is a schematic of a portion of the pneumatic system. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]    In reference to the FIGS.  1 - 9 , shown in the drawings is an apparatus comprising a weldment of members providing a rigid frame structure  100  having an upper flat elevated table surface  101  supported on a plurality of horizontally spaced vertically disposed posts  102 .  
         [0030]    A web, sheet, or roll of material  200 , to be pleated, is supplied from a supply source such as a roll  201  or optionally a stack, and passes under and then over respective horizontally disposed, vertically spaces apart rollers  202  and  203 . Upper roller  203  is journal led on the frame structure and located with the upper surface thereof slightly higher than the table surface while the lower roller  202  is journal led on a pair of spaced apart arms  205 , (see FIGS. 2 and 3), adjacent one end thereof. The other ends of the arms  205  are fixed to a shaft  206  which in turn is journal led as at  207  on the rigid frame structure by suitable bearing blocks. The lower roller serves as a web tensioning roller.  
         [0031]    The web of material is formed into a series of pleats as indicated at  208 , (see FIGS.  5 - 8 ), by a pair of relatively movable plates of pleating and web feeding units  500 ,  600 . These units are powered by a motor and gear box unit  300  thorough a system of inter-related linkages and pneumatic cylinder units. Adjustments are provided permitting changing the amplitude of the pleats as maybe desired for different applications.  
         [0032]    The power unit  300  includes an electric motor  301  mounted on the rigid frame structure that is drivingly connected to a gear box  302  having a double ended output shaft  303 . First and second arms  304 ,  305  are mounted on respective opposite ends of the shaft for rotation therewith. The arms (180 degrees out of phase) and the shaft together provide a crank arm with one arm that, through a linkage system, reciprocally moves a vertically moveable plate of the unit  600  used to perform a pleating operation on a continuous web fed from a suitable supply of the same and the other arm and through another linkage system reciprocally moves a horizontally movable plate of the second unit  500 . The units  500  and  600  operate in conjunction with one another to form a series of pleats in the web i.e. ribbon of material.  
         [0033]    The linkage system includes a first, vertically disposed, link arm  401  pivotally connected at the lower end thereof as at  402  to the rigid frame structure  100 . A horizontally disposed second top link arm  403  as best shown in FIG. 3 is pivotally connected at one end thereof by a pin  404  to the upper end of the link arm  401  and the opposite end is connected to the pleating unit  500  via a crossbar  405  to reciprocally move the same in a horizontal path toward (arrow C) and away (arrow D) from the unit  600 .  
         [0034]    The second web pleating unit  600  is mounted on the upper end of a pair of vertically disposed, horizontally spaced apart rods  410  located at respective opposite sides of the table top. The rods  410  are rigidly interconnected at their lower end by a cross bar  411  and are slidably mounted in tubular members  412  secured to the rigid frame structure. The rods  410  are thus movable and guided along a predetermined vertical path.  
         [0035]    A first feed air cylinder unit  415  is connected at one end thereof to the drive shaft arm  304  by a pivot pin  304 A (see FIG. 5) and a second air cylinder unit  416  has one end there of connected in a similar manner by a pivot pin  305 A (see FIG. 3) to the other drive shaft arm  305 . The pivot pins are adjustably movable on the respective arms in a direction toward and away from the axis of rotation of the shaft  303  and thereby provides means to selectively vary the stroke of the push-pull units  415 ,  416 . The opposite ends of the air cylinder units  415 ,  416  are connected respectively to the link arm  401  and the cross-bar  411 . A third air cylinder unit  417  is anchored at one end thereof by a pin  418  to the rigid frame structure and at the other opposite end by a pin  419  to the link arm  401 . This cylinder unit  417  serves to restrain movement of the link arm  401  (lock or float) as and when desired as dictated by the central processing unit for the operation at hand. The air cylinder unit  415  has a valve control unit  415 A actuated by signals from a central processing unit for controlling the acceleration, deceleration and lost motion connection.  
         [0036]    From the foregoing it can be seen pleating units  500  and  600  are controllably moved by respective air cylinder units  415  and  416  and these in turn are moved and/or extended and retracted in timed interrelated relation by the motor gear box unit  300  and suitable controls in the pneumatic circuit. The pneumatic circuit is schematically illustrated in part in FIG. 4.  
         [0037]    The unit  500 , connected to the cross-bar  405  located under the table top moves the unit reciprocally in a horizontal path toward (arrow C) and away (arrow D) from unit  600  which in turn moves reciprocally along a vertical path in a direction toward (arrow B) and away (arrow A) away from the table top  101 . The amount of movement of the respective units can be varied by adjusting the position of the pivot pins for the pivotal connection of the respective cylinder units  415 ,  416  to the arm associated therewith. This effectively varies the eccentricity of the pivot pins and axis of rotation of the shaft  301 . The pneumatic cylinders can be controlled through a system of valves, sensors (positioned at top dead center of each of the crankshafts), and a central processing unit such that they can control the acceleration and deceleration of the units  500  and  600  and/or act a lost motion connection in the drive system for whatever timing in the interrelated movement thereof maybe desired for the job at hand.  
         [0038]    The unit  500  includes a plate like member  501  that projects upwardly from the upper surface  101  of the table. The plate has a flat face  502  disposed generally perpendicular to the horizontal table surface. Mounted on the lower end of the member  501 , for movement therewith and relative thereto, is a clamp bar  503 . Movement of the clamp bar toward the lower edge of the plate  501  is indicated by the arrow H and the opposite direction i.e. away by the arrow J. The plate  501  is connected at opposite ends thereof by a respective one of a pair of pneumatic cylinders  504  to a pair of slide blocks  505  which in turn are slidably mounted on a respective one of a pair of horizontal rails  506  fixed to the rigid structure. The pair of pneumatic cylinders are located one at each side of the table top surface and move the plate  501  up and down respectively a selected distance toward and away from table surface  101 . A web clamp bar  503  is located below the lower edge of the plate  501  and is movable in a direction toward and away from such lower edge for respectively clamping and releasing a web of the material to be pleated disposed there between. A roller type cam member  508  is mounted on each of the respective slide blocks  505  and engages an abutment fixed to the crossbar  405 . Rotation of the cam first moves the plate  501  in a direction away from and then toward the unit  600 . This reverse movement is indicated by an arrow E.  
         [0039]    The unit  600  has a vertical plate  601  with a flat vertical face  602  disposed in face-to-face relation with the face  502  of the unit  500  and parallel thereto. As previously described the plate  601  is reciprocally movable toward (arrow B) and away (arrow A) from the table surface  101 .  
         [0040]    The sequence of movements of the plates  501  and  601  to form a pleat in the ribbon  200  of material will now be describe with reference arrows A-G and H that indicate the direction of travel of the plates as follows:  
         [0041]    A—movement of plate  601  in a direction away from the surface  101 ;  
         [0042]    B—movement of plate  601  in a direction toward the surface  101 ;  
         [0043]    C—movement of plate  501  toward plate  601 ;  
         [0044]    D—movement of plate  501  away from plate  601 ;  
         [0045]    E—reverse movement of plate  501  a small amount away from it&#39;s position adjacent the plate  601  and then toward the plate  601 ;  
         [0046]    F—upward movement of plate  501  in a direction away from the table surface  101 ;  
         [0047]    G—downward movement of the plate  501  in a direction toward the table surface  101 ;  
         [0048]    H—movement of the clamp bar  503  in a direction toward the lower edge of the plate  501  to grip there between the web  200 ; and  
         [0049]    J—movement of the clamp bar  503  in a direction away from the lower edge of the plate  503  to release the web.  
         [0050]    Referring to FIG. 4, the plates  501  and  601  are shown spaced apart and the clamp bar  503  located adjacent the lower edge of the plate  501  to clampingly grip the web  200  (omitted from FIG. 4) there between. With the web  200  clamped between the lower edge of the plate  601  and the table top  101  the plate  501  is moved in the direction of arrow C drawing with it the next length of web to be formed into a pleat and pushing the upstream length of the web between the two plates  501 ,  601  causing a fold to form between the two plates. Pressure to this double layer is applied by pneumatic cylinder  430  (see FIG. 9) which forces the plate  501  toward the plate  601 . The web is pressed between the bottom edge of the plate  601  and the table top and thus is prevented from moving forward. The plate  601  then moves in the direction of arrow A an amount sufficient to clear the pleat i.e. to an elevation higher than the crest of the pleat. Plate  501  then moves in the direction of arrow E causing the pleat to pass under the plate  601  and then the plate  601  moves in the direction of arrow B to clamp the web between the lower edge of the plate and the table surface  101 . Plate  501  then moves slightly upwardly in the direction of arrow F and at the same time the clamp bar  503  moves in the direction of arrow J releasing the grip on the web. With the web no longer gripped by the plate  501  the plate  501  then moves in the direction of arrow D returning to the position shown in FIG. 6 to start a new cycle by the clamp bar first moving in the direction of arrow H to clampingly engage the web and then the plate and clamp bar as a whole moves in the direction of arrow C to repeat the cycle and form the next pleat.  
         [0051]    It is obvious from the foregoing the arrows B, G, and J are in the same direction, i.e. vertically downward toward the table top but designate travel of the different respective components  601 ,  501  and  503  as a unit, and clamp bar  503  and the opposite upward direction of these respective components are indicted by arrows A, F and H.  
         [0052]    The newly pleated web passes through a tunnel  700  downstream from the unit  600 . The tunnel is provided by the table top surface  101  and the lower face of a plate  701  adjustably mounted on the rigid frame structure for movement in a direction toward and away from the surface  101 . The plate is supported adjacent each of the four corners thereof by a respective one of four threaded rods  702 . The edges of the plate, mid-length there along, have a thumb screw  703  the stem of which slides in a slot  704  in a bracket  705  secured to and projecting upwardly from the rigid frame structure. Downstream of the tunnel there is a knife unit  800  for cutting the pleated strip into selected lengths. The machine described in the foregoing is capable of making pleats in a continuous ribbon of material and the amplitude of the successive pleats can readily be changed by changing the eccentricity of the pivotal connection of the pneumatic cylinders  415  and  416  to the respective arms of the crank arm. When there has been a new setting the crank arm goes through about three revolutions during which time the cylinder units  415  and  416  function as a lost motion connection in the respective drive trains previously described. The respective cylinder units have sensors which feed signals to the CPU indicative of the length of stroke required for the pleats and thereafter the computer controls the operation for continuous operation at the new setting. Moreover, the length of the stroke can also be changed together or independently of the number of strokes.  
         [0053]    In operation, the pair of plates grippingly engage the web of material on the table top surface as the one plate  501  i.e. the pleater plate moves in a direction toward the escapement plate  601 . In the forgoing described embodiment the plate  501  has a bar on the lower edge thereof to releasably grip the web therebetween. As an alternative the lower edge of the plate  501  could have a series of short pointed pins, or the equivalent for example one part of hook and loop faster that cooperates with the surface of the web material to grip the same, pointing downwardly to snag the surface of the web of material on the table top. The table top is a smooth slippery surface and the gripping force required need only be sufficient to push the material ahead of the pleater plate as it moves toward the escapement plate and draw enough material from the supply roll for the next pleat. Of course it is contemplated that the smooth table top surface could be replaced by a series of rails or perhaps perforated surface.  
         [0054]    Thus, the preferred embodiments of the pleating apparatus described heretofore provides a method of forming pleats in a strip of material comprising the steps of: drawing the strip of material along a predetermined generally horizontal path; forming pleats therein by a pair of pleat forming plates that are moveable relative to one another and a fixed structure defining the horizontal path; gripping the strip of material by the plates at a pair of positions spaced apart from one another longitudinally along the strip; moving the plates relative to one another and the fixed structure to bring the plates together while maintaining the grip on the strip of material and thereby forming a pleat between the plates and pleats disposed at a higher elevation higher than the that of the predetermined path; and repeating the sequence to form a plurality of pleats.  
         [0055]    The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modification will become obvious to those skilled in the art upon reading this disclosure and may be made upon departing from the spirit of the invention and scope of the appended claims. Accordingly, this invention is not intended to be limited by the specific exemplifications presented hereinabove. Rather, what is intended to be covered is within the spirit and scope of the appended claims.