Abstract:
A pleating machine ( 20 ) is provided which allows extremely rapid, uniform pleating of flexible, tubular bodies ( 28 ), thereby eliminating the arduous and time-consuming task of manual pleating. The machine ( 20 ) includes an upper, stationary, female tubular jaw ( 90 ) and a lower, reciprocal, male tubular pleating jaw ( 92 ) which are oriented in superposed, substantially axial alignment, along with a drive assembly ( 26 ) serving to vertically reciprocate lower jaw ( 92 ). An elongated rod-type body support ( 24 ) extends downwardly through the upper jaw ( 90 ) and presents a pleating surface ( 88   a ), so that upon reciprocation of lower jaw ( 92 ), the jaw lugs ( 105 ) successively engage the body ( 28 ) to form pleats ( 162, 164 ). The pleats ( 162, 164 ) are retained by keeper structure including inwardly extending female jaw segments ( 98 ) and weighted slide ( 89 ) mounted on support ( 24 ).

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention is broadly concerned with an improved pleating machine permitting rapid, uniform pleating of flexible tubular bodies, such as tubular braided fabric. More particularly, the invention is concerned with such pleating machines, and pleating methods, wherein the machine includes a pair of aligned, tubular pleating jaws together with a drive assembly for generating relative reciprocal movement between the jaws; during jaw movement, the tubular body is successively engaged and uniform pleats are formed.  
           [0003]    2. Description of the Prior Art  
           [0004]    In the production of certain types of aircraft crew oxygen masks, there is a need for a series of pneumatically expandable tubes which are used as mask harness components. For example, U.S. Pat. No. 4,915,106 describes a crew mask of this type, wherein the harness tubes may be inflated to expand the tubes and thus facilitate rapid donning of the mask; once donned, the harness tubes are deflated so that the mask is firmly positioned on the user&#39;s head. Such expandable harness tubes are made up of a synthetic resin (e.g., silicone rubber) central tube surrounded by a braided fabric such as Nomex. The Nomex restrains the radial expansion of the silicone tube, while permitting axial expansion thereof. However, in order to accomplish this result, the surround Nomex is in a pleated condition when the inner tube is in its relaxed, unexpanded condition.  
           [0005]    In the past, it has been necessary to manually pleat the Nomex about a central silicone rubber tube. This has been done by workers who successively engage and shift small portions of the Nomex to create the desired pleated condition. This is an arduous, time-consuming task, made more difficult by the fact that the pleats must be very uniform in order to insure proper operation of the harness tubes. Generally, when manual pleating is done by an experienced worker, each tube takes at least about 15-20 minutes to complete.  
           [0006]    Mechanical pleating devices have been proposed in the past, but none are suited for pleating of tubular bodies such as flexible Nomex. For example, U.S. Pat. No. 3,343,220 describes an apparatus for corrugating and compressing flexible plastic tubing. In use, a flexible tube is circumferentially compressed through the use of pressurized air, whereupon a shiftable piston is employed to complete the pleat. This is an excessively complex mechanism which would be difficult to use efficiently. U.S. Pat. No. 3,012,604 describes and apparatus for pleating paper tubes. In this device, a feed pipe conveys a workpiece to a corrugating station where radially movable jaws operate on the workpiece to create pleats. U.S. Pat. No. 5,064,598 describes a pleating device used to pleat continuous web materials in order to create filter inserts. Finally, U.S. Pat. Nos. 5,510,071, 5,560,941, 5,522,718, and 5,372,774 are all directed to devices for the production of rigid corrugated synthetic resin tubing.  
           [0007]    There is accordingly a need in the art for a simplified apparatus designed for the rapid and efficient pleating of flexible tubular materials.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention overcomes the problems outlined above and provides an improved pleating machine operable for pleating elongated flexible tubular bodies. Broadly speaking, pleating machines in accordance with the invention include a jaw assembly having a pair of tubular pleating jaws in substantial axial alignment, with a support operable to maintain a tubular body in a pleating position passing through the pleating jaws. A drive assembly is operably coupled with the jaw assembly for generating relative reciprocal movement between the jaws in order to successively engage the tubular body and form pleats therein. Keeper structure is also provided which is operable to retain the pleats upon formation thereof.  
           [0009]    Preferably, the jaw assembly includes an upper, stationary female jaw and a mating, lower shiftable male jaw. Each of these jaws is of annular configuration with interfitting jaw legs. The shiftable lower jaw is reciprocated through a pneumatic piston and cylinder drive assembly, controlled through a switchable directional valve, preferably a reciprocating directional control valve. The male jaw includes a plurality of circumferentially spaced lugs which engage the tubular body, pushing a pleat thereof upwardly along the length of the inner support until the pleat passes inwardly extending keeper segments forming a part of the female jaw legs.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a front elevational view of the preferred pleating machine in accordance with the invention;  
         [0011]    [0011]FIG. 2 is an enlarged, fragmentary rear view of the pleating machine, illustrating the pleating jaws and drive assembly;  
         [0012]    [0012]FIG. 3 is an enlarged, fragmentary sectional view taken along line  3 - 3  of FIG. 2;  
         [0013]    [0013]FIG. 4 is an enlarged, fragmentary central vertical sectional view of the machine, illustrating the pleating jaws in the separated and open position thereof;  
         [0014]    [0014]FIG. 5 is a view similar to that of FIG. 4, but depicting the pleating jaws in the closed, pleating position thereof;  
         [0015]    [0015]FIG. 6 is an enlarged, vertical sectional view depicting one of the piston and cylinder assemblies forming a part of the drive assembly, in the extended position thereof;  
         [0016]    [0016]FIG. 7 is an enlarged, exploded perspective view illustrating the pleating jaws and support rod;  
         [0017]    [0017]FIG. 8 is a fragmentary view illustrating the preferred straight line clamp used for positioning of the support rod;  
         [0018]    [0018]FIG. 9 is a schematic flow diagram illustrating the interconnection between the valve assembly and the piston and cylinder assemblies forming a part of the drive;  
         [0019]    [0019]FIG. 10 is an enlarged, sectional view illustrating positioning of the support rod and flexible tubular body to be pleated, with the latter extending through the open pleating jaws prior to a pleating operation;  
         [0020]    [0020]FIG. 11 is a sectional view similar to that of FIG. 10, but illustrating the support rod and tubular body in a pleating position;  
         [0021]    [0021]FIG. 12 is a view similar to that of FIG. 11, but illustrating the lower male jaw shifted upwardly to engage the tubular body so as to create an initial pleat;  
         [0022]    [0022]FIG. 13 is a view similar to that of FIG. 12, but showing the lower jaw in its shifted away position from the upper female jaw during the course of pleating of the tubular body;  
         [0023]    [0023]FIG. 14 is a view similar to that of FIG. 13, but illustrating the pleating jaws in their open position with the tubular body fully pleated;  
         [0024]    [0024]FIG. 15 is a sectional view depicting the elongated rod and finished pleated body removed from the pleating machine, prior to complete removal of the weighting tube;  
         [0025]    [0025]FIG. 16 is a view similar to that of FIG. 15, but illustrating the weighting tube removed;  
         [0026]    [0026]FIG. 17 is a view similar to that of FIG. 16, but showing the placement of a synthetic resin tube over the upper end of the rod, prior to placement of the pleated body thereover;  
         [0027]    [0027]FIG. 18 is a sectional view similar to that of FIG. 17, but showing the finished pleated body shifted over the synthetic resin tube; and  
         [0028]    [0028]FIG. 19 is a sectional view depicting the synthetic resin tube with the pleated body thereon, with clamps used to hold the pleated body in place. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]    Turning now to the drawings, a pleating machine  20  is illustrated in FIG. 1, and broadly includes a frame assembly  22 , an elongated vertically extending tube support  24 , jaw assembly  25 , and drive assembly  26 . The machine  20  is designed to efficiently pleat an elongated tubular body  28  of flexible material such as the above-described Nomex material.  
         [0030]    In more detail, the frame assembly  22  includes a base plate unit  30  including a lower base member  32  apertured as at  33 , as well as an upper base plate  34  having an aperture  35  therethrough. A series of coil spring vibration dampeners  36  are used to interconnect the member  32  and plate  34 , each of the dampeners  36  including respective upper and lower attachment plates  38 ,  40  secured to the plate  34  and member  32  via fasteners  42 , as well as intermediate coil spring sections  44 . A resilient valve stop  45  is secured to the upper face of plate  34  for purposes to be made clear.  
         [0031]    The frame assembly  22  further includes a pair of laterally spaced apart upright threaded standards  46 ,  48  which are secured to plate  34  by means of nuts  50 . The standards are equipped with a set of lower collars  52 ,  54  which support a horizontal, generally T-shaped stationary plate  56 . As best seen in FIGS. 2 and 3, the plate  56  is provided with three spaced openings  58 ,  60 ,  62  between the collars  52 ,  54 , as well as a valve stop  64  vertically adjustable by means of rotatable knob  66 . A pair of upper collars  68 ,  70  are also secured to the standards  46 ,  48  and support a transversely extending, centrally apertured mount  72 . A De-Sta-Co straight line clamp  74  is secured to mount  72  by way of nut  76 , and has a downwardly extending leg  78  terminating in a friction fitting  80  (see FIGS. 1 and 8).  
         [0032]    The tube support  24  is in the form of an elongated, stepped rod  82  presenting an uppermost section  84  of reduced diameter, as well as a lower section  86  of greater diameter, the latter terminating in a smoothly tapered and converging bullet lowermost end  88  presenting a pleating surface  88   a . The upper end of section  84  is sized for a frictional fit connection within fitting  80 , during use of the machine  20  as further described below. In use, the support  24  is also equipped with a weighted tubular slide  89  which is telescoped over the section  86  of the rod; the slide  189  has an annular weighted upper end  89   a  and a depending tubular segment  89   b.    
         [0033]    The jaw assembly  25  is made up of upper female and lower male tubular jaws  90 ,  92  which are in substantial axial alignment, with the jaw  90  being stationary and disposed above jaw  92 . In more detail, the female jaw  90  includes an annular header section  94  with three circumferentially spaced apart legs  96  depending from the header section. The lowermost end of each leg  96  includes an inwardly extending keeper segment  98  which is important for purposes to be made clear. The lower male jaw  92  includes an annular base  100  with four upwardly extending, circumferentially spaced legs  102  separated by vertical recesses  104 ; the legs  102  include an inwardly extending engagement lugs  105 . A pair of resilient O-rings  106  are located about the exterior surfaces of the legs  102  as best seen in FIG. 7. The legs  96  are sized and oriented so as to fit within the recesses  104  during pleating operations.  
         [0034]    The drive assembly  26  includes a pair of laterally spaced apart pneumatic piston and cylinder assemblies  108 ,  110  each having a vertically oriented cylinder  112  and a downwardly extending piston rod  114 . As best seen in FIG. 6, the lower end of each rod  114  is secured to base plate  34  by means of nut  116 . A resilient bumper  118  and resilient O-ring  120  are disposed about rod  114 , with the bumper  118  resting atop base plate  34 . A cross plate  122  extends between the assemblies  108 ,  110 , and is secured to the rods  114  by upper nut  124 . The cross plate  122  includes a central opening  126  in registry with opening  60  of plate  56 . A directional valve  128  also forms a part of the assembly  26  and is supported by means of an L-bracket  130 . The lateral extent of the bracket  130  is secured to cross plate  122  and has a central opening  132  in registry with opening  126 . The valve  128  is itself conventional and includes valve body  134  having exhaust ports  136  and upper and lower valve pins  138 ,  140 .  
         [0035]    Pneumatic control circuitry  142  is provided to properly interconnect directional valve  128  and the piston and cylinder assemblies  108 ,  110 . Such circuitry is schematically illustrated in FIG. 9 and includes manual safety valve  144  and on-off pneumatic switch  146 . A first conduit  148  extends from pump  144  to the input of switch  146 , and a second conduit  150  extends from the switch output to the directional valve input  152 . Two branched valve output lines  154 ,  156  extend from the output of the directional valve and are respectively coupled to the upper and lower ends of the assemblies  108 ,  110 .  
         [0036]    As best illustrated in FIGS.  10 - 14 , the lower male jaw  92  is clamped between cross plate  122  and bracket  130 , i.e., the base  100  is received within corresponding annular recesses formed in the cross plate  122  and  130 , so that the jaw  92  is positioned in an upright orientation in axial alignment with the openings  126  and  132 . Similarly, the upper jaw  90  is clamped between the recessed underside of T-shaped plate  56  and annular clamping plate  158 , so that the jaw  90  is in registry with central opening  60 .  
         [0037]    The purpose of drive assembly  26  is to rapidly reciprocate cross plate  122 , thereby vertically shifting valve  128  and lower jaw  92 . Thus, when directional valve  128  is in the FIG. 9 position thereof, pressurized air is delivered via line  154  to the assemblies  108 ,  110 , thereby serving to extend the rods  114  while air is exhausted from the corresponding port  136 , and simultaneously lowering cross plate  122  and lower male jaw  92 . When the rods  114  reach their lowest extent, valve pin  140  of directional valve  128  engages stop  45 , causing the directional valve  128  to shift and deliver pressurized air via output line  156  to the bottoms of the assemblies  108 ,  110 . This of course retracts the piston rods  114 , causing cross plate  122  and jaw  92  to move upwardly until upper valve pin  138  comes into engagement with valve stop  64 . In this fashion, the cross plate  122  and lower jaw  92  are rapidly moved in an up and down reciprocating fashion.  
         [0038]    Operation  
         [0039]    The operation of machine  20  will now be described in connection with pleating of tubular body  28  of flexible material, such as Nomex. In the first step, the slide  89  is telescoped over section  86  of rod  82  and the upper end of tubular body  28  is telescoped onto the bullet end of the rod; a stretch of tape  160  is used to secure the upper end of the body  28  to the outer surface of tubular slide section  89   b  (see FIGS. 10 and 11). Next, the depending portion of body  28  is threaded downwardly through the open jaws  90 ,  92 , i.e., it is passed through opening  58 , upper female jaw  90 , lower male jaw  92 , opening  126  and ultimately through base openings  35 ,  33 . At this point, the upper reduced diameter section  84  of rod  82  is secured within fitting  80 , and the clamp  74  is manipulated so as to lock the rod  82  in place. This initial orientation of the rod is depicted in FIG. 11, where it will be seen that the rod passes through the lowermost opening of upper jaw  90  with in the extreme lower bullet end  80  passing into the confines of lower jaw  92  adjacent the engagement lugs  105 .  
         [0040]    The drive assembly  26  is then actuated in order to begin the pleating process. Referring to FIG. 12, it will be seen that as the lower jaw  92  is elevated, the lugs  105  come into frictional contact with the outer surface of tubular body  28  and, by virtue of the presence of the pleating surface  88   a , an initial pleat  162  of material is formed and pushed upwardly past the keeper segments  98  and against the bias of slide  89 . Upon retraction of the lower jaw  92 , the initial pleat  162  is retained between the keeper segments  98  and the lower end of weighted slide segment  89   b.    
         [0041]    Referring now to FIGS. 13 and 14, it will be seen that continued up and down reciprocation of lower jaw  92  creates successive pleats  164 , all of which are retained between the keeper structure cooperatively defined by the segments  98  and weighted slide  89 . The pleating operation continues until substantially the entirety of the tubular body  28  is plated.  
         [0042]    Attention is next directed to FIGS.  15 - 19  which illustrate how the pleated body  28  is applied to a synthetic resin tube  165 . In particular, in the first step the support  24  is removed from the machine  20  by releasing the clamp  74  and detaching the upper end of rod section  84  from fitting  80 . This is done carefully so as to prevent the lower end of the pleated body  28  from passing downwardly over bullet end  88 .  
         [0043]    Next, the weighted slide  89  is removed from the support  24  leaving the pleated body  28  in place as shown in FIG. 16. At this point, the tube  164  is telescoped over reduced diameter upper section  84  of rod  82 , and is temporarily secured thereto by tape  166 . At this point, the entire pleated section  28  is slid upwardly along the length of the rod over the tube  165  until it assumes the position of  118 . Finally, the upper and lower ends of the pleated body  28  are temporarily secured to tube  165  by clamps  168 , and the tube  165  is then removed from the rod  82 . The assembly of the tube  165  with the pleated body  28  telescoped thereover can then be used in the manufacture of an aviation mask or the like.