Abstract:
Apparatus and a method for assembling a stretchable cover upon a rigidly backed foam cushion wherein the cushion lateral dimensions vary along its length. The degree of stretching of the cover varies during cushion/cover assembly as controlled by cams and cam followers to permit wrinkle-free covering of backed foam cushions of irregular configuration.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention pertains to an apparatus and method for assembling a stretchable cover upon a rigidly backed foam cushion.  
           [0003]    2. Description of the Related Art  
           [0004]    Cushioned and covered components are used in a, variety of products such as automobiles, furniture and building components wherein a plush, soft, attractive surface is desired. In such instances, it is common to use a relatively rigid backing of wood or paperboard in combination with an expanded foam affixed to the backing whereby the foam cushion will maintain a predetermined shape and configuration.  
           [0005]    When covering a backed foam cushion with a flexible cover, such as made of fabric, vinyl, leather or the like, it is necessary that the cover be dimensionally fabricated accurately so as to closely fit and encase the backed cushion to minimize the occurrence of wrinkles and unsightly ribs or waves in the cover. Obtaining a wrinkle-free covering of a backed cushion is difficult in that the cover must closely and firmly encase the backed cushion, and because of the close tolerances, difficulty is encountered in assembling the backed foam cushion and cover.  
           [0006]    Known apparatus for assembling backed foam cushions and covers have not been readily adaptable to high production assembly techniques, and considerable hand work is often required to make the cover acceptably fit and enclose the backed foam cushion. Such hand work is slow and expensive, and if care is not taken to properly position the cover on the backed foam cushion, wrinkles and ridges will appear which aesthetically detract from the finished product.  
         OBJECTS OF THE INVENTION  
         [0007]    It is an object of the invention to provide a method and apparatus for assembling a rigidly backed foam cushion and a stretchable cover wherein the cover may be quickly and accurately placed upon the backed foam cushion in a tight fitting and wrinkle-free manner.  
           [0008]    Yet another object of the invention is to provide apparatus and a method for assembling backed foam cushions and stretchable covers wherein backed foam cushion assemblies of irregular lateral configuration can be quickly and accurately covered with a stretchable cover, and wherein the cover is stretched in accord with the configuration of the backed cushion assembly.  
           [0009]    Yet a further object of the invention is to provide apparatus and a method for assembling a rigidly backed foam cushion and stretchable cover wherein the degree of stretching of the cover that occurs during assembly can be varied in a predetermined manner by cams and cam followers, and in accord with the lateral configuration of the backed cushion.  
         SUMMARY OF THE INVENTION  
         [0010]    In the practice of the invention, it is the purpose to assemble a rigidly backed foam cushion with a stretchable cover wherein, even though the lateral dimension of the cushion configuration may be variable, the stretching of the cover during assembly can be controlled to be provide an optimum fit between the cover and backed foam cushion to eliminate wrinkles and ridges.  
           [0011]    The apparatus of the invention is preferably vertically oriented having an upper ram portion and an assembly portion located below the ram portion.  
           [0012]    A pair of carriages are mounted on the frame assembly portion in side-by-side relationship movable upon elongated guides or ways whereby the carriages may move toward or away from each other in a lateral direction. Each of the carriages supports a pair of spaced plate-like stanchions which are mounted at their lower end upon the associated carriage and extend upwardly toward the frame ram portion. Two stanchions are mounted upon each carriage and the upper ends of the stanchions are unsupported whereby the stanchions are cantilever supported in a vertical position. The stanchions mounted upon a common carriage are spaced from each other by a dimension slightly greater than the thickness of the backing and foam cushion assembly, and the stanchions of the two carriages are in lateral alignment whereby the four stanchions together define a “slot” of a thickness slightly greater than the backed cushion assembly.  
           [0013]    Each of the carriages includes a roller cam follower received within a cam slot formed in a cam plate mounted on the frame upon vertically disposed guides whereby the cam plate is capable of moving toward and away from the frame assembly portion.  
           [0014]    In the preferred arrangement, the cam plate is connected to the ram such that the cam plate will move with the ram toward and away from the frame assembly portion. As the cam slots in the cam plate will be of a configuration usually complementary to the lateral configuration of the backed cushion assembly, the engagement of the carriage cam followers in the cam plate cam slots will cause the carriages to move laterally as the ram is lowered toward the carriages and frame assembly portion.  
           [0015]    To further customize the stretching of the cover as the backed foam cushion is inserted therein, the outer edges of the stanchions, i.e. those stanchion edges laterally facing away from each other and the center of the frame and which engage the cover, may also be configured in accord with the shape of the foam cushion and cover to facilitate entry of the cushion into the cover and assure fitting of the cover to the cushion to produce a wrinkle-free product.  
           [0016]    The cover is turned inside out and placed over the top of the stanchions and as the cushion is pushed into the pocket defined by the cover by the ram, the cover folds inwardly over the top of the stanchions while being stretched laterally by the stanchions. Accordingly, the cover is automatically removed from the stanchions as it is stretched thereby and as the cushion assembly is received within the cover. At the end of the ram stroke, the cushion assembly will be completely encased within the cover, the cover will have now been removed from the stanchions, and the assembly between the cushion and its cover is now complete, and the cushion/cover assembly will be located between the carriage stanchions.  
           [0017]    The ram is now retracted away from the frame assembly portion. This movement causes an ejector head located between the stanchions to move upwardly with the ram as it retracts. The ejector head will engage the assembled cushion and cover and remove the same from between the stanchions as the ram retracts. This permits the operator to remove the assembled cushion and cover from the machine once the ram is fully retracted. Thereupon, a new cover may be inserted upon the stanchions and a backed foam cushion mounted upon the ram, and the assembly cycle repeated.  
           [0018]    The practice of the invention permits a backed foam cushion to be quickly and accurately encased within a stretchable cover in a wrinkle-free manner, and even though the cushion may have a variable lateral dimension, the automatic control of the stretching of the cover by the movable stanchions, whose position is determined by the cam followers and cam slots, permits an improved assembly procedure than that previously obtainable, and permits a higher quality finished product to be achieved. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    The aforementioned objects and advantages of the invention will be appreciated from the following description and accompanying drawings wherein:  
         [0020]    [0020]FIG. 1 is a front elevational view of a cushion and cover assembly machine in accord with the invention, a backed foam cushion being shown in dotted lines, and no cover is mounted upon the carriage stanchions,  
         [0021]    [0021]FIG. 2 is an elevational view of the assembly apparatus of FIG. 1 as taken from the right side thereof,  
         [0022]    [0022]FIG. 3 is a detail perspective view of the frame assembly portion illustrating the carriages, cam plate and cam slots, a cushion being shown in position, and prior to a cover being mounted upon the carriage stanchions,  
         [0023]    [0023]FIG. 4 is an elevational view illustrating the cam plate as taken along Section  4 - 4  of FIG. 3, and  
         [0024]    [0024]FIG. 5 is a perspective view similar to FIG. 3 illustrating a partial assembly of the foam cushion and the cover, the cover being mounted upon the stanchions and partially received upon the cushion. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    The overall appearance of cushion assembly apparatus in accord with the invention is best shown in FIGS. 1 and 2. The apparatus constitutes a frame generally indicated at  10  upon which is mounted a ram portion  12  and an assembly portion  14 . In the drawings, the frame is shown in a vertical orientation, which is the usual manner of positioning the frame such that the ram portion  12  extends above the assembly portion  14 . However, it is to be appreciated that the invention could be practiced if the ram portion  12  and assembly portion  14  were horizontally related.  
         [0026]    The frame  10  includes four legs  16  upon which a table  18  is mounted which comprises the support for the assembly portion  14 . Extensions of the rear legs  16  constitute a support for the control box  20  in which the controls for the apparatus are located.  
         [0027]    A ram support column  22  arises from the table  18  having an upper end  23  upon which a ram cylinder  24  is mounted. The ram cylinder  24  is preferably air operated, is of the expansible chamber type, and includes a downwardly extending piston  26  terminating in a piston head or block  28  from which the cushion anchor  29  is attached. The column  22  includes a bracket  30  which constitutes the upper support for a pair of parallel cylindrical guides  32  which extend downwardly through the table  18  and are affixed at their lower end to the lower region of the frame  10 . The guides  32  are parallel to each other, and the direction of movement of the piston  26 , and a cam plate  34 , preferably formed of aluminum, is reciprocally mounted upon the guides  32  and adapted to be translated along the guides  32  with movement of the piston  26  by means of a tie rod  36  affixed to the cushion anchor  29  and the cam plate  34 .  
         [0028]    A pair of ways or guides  38  are mounted on the table  18 , FIG. 3, having a length at right angles to the cam plate guides  32 . The ways  38  are parallel to each other, and support carriages  40  and  42  wherein the carriages are linearly reciprocally mounted on the ways  38  in a manner later described. The carriages  40  and  42  are movable toward and away from each other in a linear manner on the ways  38  and in a direction lateral to the frame  10  and ram  24 .  
         [0029]    Each of the carriages  40  and  42  include a T-bracket  44  affixed thereto and extending above the associated carriage. The brackets  44  constitute the support for the cover stretching stanchions  46 . As will be appreciated from FIG. 3, identical stanchions  47  are mounted upon carriage  40 , while identical stanchions  49  are mounted upon carriage  42 .  
         [0030]    The stanchions  46  mounted on a common carriage are identical to each other, and the stanchions mounted on opposite carriages are mirror images of each other. Each stanchion includes a cantilevered top edge  48  and a radius  50  which blends into the stanchion outer edge  52 . The outer edges  52  of stanchions  47  are disposed in the lateral direction with respect to the height of the frame  10  opposite to the direction of the outer edges of stanchions  49 .  
         [0031]    The stanchions  46  are of a plate-like material, and may be formed of a rigid synthetic plastic material, and are affixed in a cantilevered manner to their associated carriage T-bracket  44  by fasteners  54  located adjacent the lower edges of the stanchions. The stanchions mounted upon a common carriage  40  or  42  are in a spaced relationship to each other as will be appreciated from FIG. 3. For instance, the stanchions  47  mounted upon carriage  40  are spaced apart a distance adapted to receive the foam cushion assembly which is inserted between stanchions  47 . In a similar manner, stanchions  49  mounted upon carriage  42  are also spaced from each other as to receive the cushion assembly therebetween. Further, the void or spacings between stanchions mounted upon a common carriage are in alignment with the spacing between the stanchions of the other carriage wherein an elongated space or slot is defined by the stanchions  47  and  49  capable of receiving the backed cushion assembly.  
         [0032]    A cam roller  56  is mounted on each of the T-brackets  44  for the carriages  40  and  42 . The cam rollers  56  are received in one of the cam slots  58 , FIG. 4, defined in the cam plate  34 . As will be appreciated from FIG. 4, the cam slots  58  are obliquely related to each other, and as will be later appreciated, the configuration of the cam slots  58  is determined by the extent of stretching of the cushion cover desired during assembly.  
         [0033]    An ejector rod  60 , FIG. 5, extends upwardly through the table element  18  in alignment with the ram piston  26 . The ejector rod  60 , at its upper end, includes an ejector head  62  located between the stanchions  46 , FIG. 3, and the ejector rod  60  is affixed at its end  64  to the lower end of the cam plate  34  whereby the ejector rod  60  will raise and lower in conjunction with the movement of the cam plate  34  and the ram piston  26 .  
         [0034]    In operation, the ram  24  will be operated to raise the piston  26  its maximum degree. In such instance, the cam plate  34  will be raised to the maximum extent as will the ejector rod  60 . A foam cushion  66  having a rigid backing  68  is then affixed to the cushion anchor  29  mounted to the ram piston head  28 . As will be appreciated from the dotted lines in FIG. 1, the cushion  66  includes tapered lateral edges  67 , and upon mounting the cushion and backing plate assembly to the cushion anchor  29 , the cushion will be disposed above the stanchions  46  as shown in FIG. 3.  
         [0035]    The cushion cover  70  which is in the form of a closed end tube or pocket, and is formed of a stretchable material such as fabric, vinyl, leather or the like, is turned inside out and placed over the upper edges  52  of the stanchions  46  in a manner that will be appreciated from FIG. 5. Turning the cover  70  inside out forms an open upwardly extending pocket  72  in alignment with the lower edge of the cushion  66 , and the pocket  72  extends between stanchions  47  and  49 . The majority of the cover is then pulled down over the outside of the stanchions  47  and  49  and over outer edges  52 .  
         [0036]    Once the cover  70  is located on the stanchions  46  so that the pocket  72  is in alignment with the lower edge of the cushion  66 , the ram  24  is energized with compressed air to move the piston  26  downwardly toward the frame assembly portion  14 . As the cushion  66  moves downwardly, its lowermost end will enter the cover pocket  72 , and the cushion will enter the slot between stanchions  47  and  49 . As the cushion  66  is continued to be pushed between the stanchions  47  and  49 , the engagement of the lower end of the cushion  66  with the cover  70  will push the cushion into the cover pocket pulling the cover envelope over the stanchion top edges  48  as the cover encompasses that portion of the cushion located between stanchions  47  and  49  as shown in FIG. 5.  
         [0037]    Simultaneously with the lowering of the cushion  66 , the stanchions  47  and  49  will be moving outwardly away from each other due to the lowering movement of the cam plate  34  and the force exerted on the carriages  40  and  42  by the cam rollers  56  due to the oblique configuration of the cam slots  58 . Thus, as the cushion  66  is lowering, the cover  70  will be laterally stretched by the stanchion outer edges  52  simultaneously with the cover being pulled upon the backing and cushion assembly. The degree of stretching of the cover  70  that occurs during assembly of the cover with the cushion is determined by the configuration of the cam slots  58 , and the configuration of the stanchions&#39; outer edges  52 . The configuration of the cam slots  58  and the stanchion outer edges  52  will be determined by the lateral configuration of the backing and cushioning assembly being covered so that the cover will be properly stretched to permit a wrinkle-free assembly with the backing and cushion assembly.  
         [0038]    The ram  24  will continue to lower the cushion assembly  66  until all of the cover portion  74  has been pulled into the slot between stanchions  47  and  49  which will complete the covering of the cushion assembly  66 .  
         [0039]    After the cushion assembly  66  has been completely encased within the cover  70 , the ram  24  is retracted upwardly. This upward movement of the piston  26  simultaneously moves the ejector rod  60  upwardly causing the ejector head  62  to engage the lowermost portion of the covered cushion assembly lifting the cushion assembly from between stanchions  46  so that when the piston  26  is fully retracted, the covered cushion assembly may be removed from its cushion anchor  29 . The procedure may now be repeated to cover another cushion assembly as the carriages  40  and  42  will be moved to their closest position relative to each other, FIG. 3, and another inside out cover  70  may be placed over the stanchions  46 .  
         [0040]    As the lateral dimensions of the backing and cushion assembly may vary considerably between products, the ability of the cam plate  34  to define any desired configuration of cam slot  58  permits optimum cover stretching to be achieved depending on the lateral configuration of the backing and cushion assembly. Accordingly, the apparatus of the invention provides a flexibility and customizing of cushion and cover assembly not heretofore possible.  
         [0041]    It is appreciated that various modifications to the inventive concepts may be apparent to those skilled in the art without departing from the spirit and scope of the invention.