Patent Publication Number: US-3971112-A

Title: Method of making a covered article

Description:
BACKGROUND OF THE INVENTION 
     Many processes have been taught in the prior art for forming a covered article such as an automobile seat cushion. For example it has been proposed to vacuum form an outside cover from a sheet of vinyl and then to react a foamable composition within the interior volume of the cover to form the resilient portion of the seat cushion. One difficulty encountered with such a vacuum forming method is that only a special vinyl material may be used in the process because of the depth of the draw on the material in the forming operation. The vinyl material used in the process is relatively expensive also because the material must be heat resistant. Thus a seat cushion made with a vacuum formed cover and a foamed interior has its drawbacks. 
     Another method for forming a covered article such as an automobile seat cushion is one wherein the cover of the article is formed in an injection molding operation. The mold and molding press for such a molding operation are very expensive. Also after a cover is injection molded, it has to be painted in order to obtain the proper color on the exterior surface thereof. Thus, forming a seat cushion by manufacturing the exterior cover in an injection molding operation and thereafter reacting a foamable composition therewith also has its drawbacks. 
     Still another method proposed for forming a covered article such as an automobile seat cushion is one wherein a self-skinning foam is employed. In this case, the foamable composition is reacted in a mold and it produces its own relatively thin exterior skin and a porous resilient interior. The difficulty with this process is that the weight per unit volume is higher than covered articles produced by other methods. Also the finished seat cushion is relatively hard and does not give the seating comfort desired. This type of construction also has to be painted in order to produce a finished article. Also, as another drawback to this process no cloth or vinyl material can be utilized as the foam develops its own exterior skin. 
     SUMMARY OF THE INVENTION 
     This invention is directed to a method of making a covered article, and more particularly to a method of making a covered article which may be used as a seating member. 
     In accordance with the broad concepts of the method of this invention, a covered article is fabricated in the following way. At least a pair of covering members are formed of a covering material. The covering material is impervious to a foam material which is formed from a foamable composition. The covering members are sewn together along at least one sew line to form a cover having a peripheral edge portion therearound and an interior volume. The sewing operation places openings through the cover which permit the passage of the foam material through the cover. These openings are along the sew lines of the cover. 
     A locating member is formed in a separate operation. The locating member has an inner peripheral edge portion therearound defining a central opening therein. The locating member also has locating portions between the inner peripheral edge portion and an outer peripheral edge portion. The locating member&#39;s inner peripheral edge has the same general configuration as the peripheral edge portion of the cover. 
     The peripheral edge portion of the cover is joined to the inner peripheral edge portion of the locating member. This joining may be accomplished in a sewing operation. 
     The openings along the sew lines joining the covering members together are sealed. These openings are sealed so that the foam material produced upon foaming of the foamable composition cannot flow through the openings and thus ruin the outer surface to the finished covered article. 
     The cover and joined locating member are placed in a foaming mold. The foaming mold has a mold portion containing a die surface upon which a vacuum can be drawn and an openable cover portion. The locating portions of the locating member are aligned with locating positions on the foaming mold to align accurately the cover with the die surface of the foaming mold. A vacuum is drawn on the die surface of the foaming mold thereby to draw a facing surface of the cover into contact with the die surface. This action forms an interior volume in the cover between the inner surface of the cover and the cover&#39;s peripheral edge. A charge of a foamable composition is placed into the interior volume of the cover. The cover portion of the foaming mold is closed. The foamable material is reacted to fill the interior volume of the cover with a foam material. After the foaming operation the foaming mold is opened. 
     After the foaming mold is opened, the cover, foam material and locating member are removed from the mold as a single unit. Thereafter, the locating member is removed from the cover thereby to form a covered article. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Each of the figures of the drawings is a diagrammatical sketch representing one of various steps in the method of this invention for producing a covered article such as an automobile seat cushion. 
     FIG. 1 illustrates the covering members to be sewn together to form a cover. 
     FIG. 2 illustrates the joining of a cover to a locating member. 
     FIGS. 3 and 4 illustrate the sealing of openings which were formed when the covering members were sewn together to form a cover. 
     FIG. 5 represents the positioning of the cover member and the locating member in a foaming mold. 
     FIG. 6 represents the cover located in the foaming mold prior to a foaming operation. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1 three covering members 10, 12 and 14 are shown. The members are formed from a covering material which is impervious to a foam material which is developed upon reaction of a foamable composition such as a polyurathane foam. The covering material may be, for example, an impervious vinyl sheet. The covering material may also be a cloth which has an impervious layer applied to the under surface thereof. The covering material may also be one or more plys of material, some of which plys are impervious so that the material as a whole is foamed impervious. The covering members 10, 12 and 14 are cut out of the covering material in a standard cutting operation. 
     The covering members 10, 12 and 14 are sewn together along their edges at sew lines 16 and 18 (FIG. 2) in order to form a cover, generally identified by the numeral 20. As is known in the art, the sewing operation is accomplished with the back surfaces of the covering members 10, 12 and 14 being exposed. Thus, as viewed in FIG. 2, the surface of the cover 20 shown is the one which will form the interior of the final article. In the process discussed herein, the article to be manufactured is an automobile seat cushion. 
     The sewing operation which produces the cover 20 also result in the cover having a peripheral edge portion 22 formed therearound. This peripheral edge portion has a plurality of locating apertures 24 therein for a purpose which will be described below. These apertures 24 may be formed in the members during the cutting operation described above. 
     In the sewing operation which produces the sew lines 16 and 18, a plurality of small openings are formed through the otherwise foam impervious covering material which forms the covering members. These openings are of sufficient size that when a foamable composition is foamed inside the interior of the cover, foam material will pass through such openings and either ruin the cover or, in the alternative, result in an additional operation for cleaning up the cover to make it acceptable for its intended use. 
     With reference now to FIG. 2, a locating member 26 is shown. This locating member, which can be made of a material such as cardboard, has an inner peripheral edge portion 28 therearound defining a central opening 30. The inner peripheral edge portion 28 of the locating member 26 has the same general configuration as the peripheral edge portion 22 of the cover 20. Between the inner peripheral edge portion 28 of the locating member and its outer peripheral edge portion a plurality of locating openings 32 are provided. A plurality of alignment markings 34 are also provided between the inner and outer peripheral edge portions of the locating member. 
     The peripheral edge portion 22 of the cover 20 is joined, as by a sewing operation, to the inner peripheral edge portion 28 of the locating member 26. In order to make sure that the cover is accurately aligned with the locating member, the locating apertures 24 of the cover are aligned with the alignment markings 34 of the locating member such that the center of the aperture is centered over the central one of the alignment markings. This action insures that the cover is properly located with respect to the locating member during the operation which joins these two. As stated above, in the preferred embodiment the operation which joins the cover to the locating member is a sewing operation. However, other operations such as stapling, tacking, dielectric or adhesively bonding the peripheral edge portion of the cover to the inner peripheral edge portion of the locating member are satisfactory. The only thing required of this operation is to produce a unit in which the cover 20 is joined to the locating member 26 along a plurality of joining lines 36 so that the two form a single unit. As shown in FIG. 3, these two elements are joined together with the interior surface of the cover exposed. 
     The assembled cover 20 and locating member 26 are placed on a seating buck 38 with the interior surface of the cover exposed. The seating buck defines generally the shape of the seat to be formed. A plurality of locating pins 40 on the seating buck are used in conjunction with the locating openings 32 of the locating member 26 to insure that the cover is placed in a proper position on the seating buck. The seating buck is also provided with a plurality of vacuum openings 42 through which a vacuum can be drawn on the interior of the cover which in this case is actually the surface of the cover which will form the exposed portion of the final article. When the cover is placed on the seating buck, the vacuum is drawn on the seating buck in order to pull the cover with its interior surface exposed into contact with the seating buck. 
     While the cover 20 is on the seating buck 38, the openings formed along sew lines 16 and 18 are sealed so that the foam developed upon the foaming of the foamable composition will not have an opportunity to flow therethrough. While FIG. 4 does not show the operation as being carried on the seating buck, it must be kept in mind that during this operation the cover member is located on the seating buck with the vacuum system operative so that the cover member is properly located with respect to the seating buck. 
     In accordance with the teachings of the preferred embodiment of this invention, the openings along the sew lines 16 and 18 of the cover 20 are sealed by application of a sealing tape 44, strips of which are shown in FIG. 4. Preferably, this tape is of the pressure sensitive type and is applied by unrolling the tape, cutting it to proper length and applying it over the sew lines 16 and 18. The sew lines are sealed on both sides thereof for a sufficient width that no foam may leak through the openings formed along the sew lines. 
     While the preferred way of accomplishing the sealing of the openings is one in which a pressure sensitive tape is used, many alternate ways of sealing these openings can be employed. For example, an adhesive may be applied across a width of the sew lines and then a foam impervious material may be laid over the adhesive to seal the openings. The openings may also be sealed by applying a liquid material which solidifies to form a sealant which is impervious to the passage of foam therethrough. It is also apparent that there are many alternate ways for accomplishing the sealing of these openings. The principal requirement for the operation is that it be one which can be carried out efficiently and that it be one which produces a seal for the opening that does not allow the foam material produced by reaction of the foaming composition to pass through any of the openings. 
     After the openings on sew lines 16 and 18 have been sealed and made impervious to the foam material, the cover 20 and its attached locating member 26 are removed from the seating buck 38. When the operator pulls up on the locating member to remove it and the cover from the seating buck, the cover 20 is turned inside out so that the surface of the material which will form the exposed portion of the final cover is now exposed. This conditions is shown in FIG. 5. 
     FIG. 5 illustrates the step of the process in which the cover 20 and its attached locating member 26 are positioned in a foaming mold generally identified by the numeral 46. The foaming mold has a mold portion 48 containing a die surface 50 having a plurality of fine vacuum openings (not shown) on which a vacuum may be pulled. The foaming mold also has a cover portion 52 which is generally closed during a forming operation. The mold portion 48 is also provided with locating pins 54 which are receivable in locating openings 32 of the locating member 26 to insure that the cover 20 is properly aligned with the die surface 50. 
     An operator inserts the locating member 26 and the attached cover 20 into the foaming mold 46 so that the cover 20 is placed in the mold portion 48 which has the die surface 50. A vacuum is applied to the die surface 50 and the cover is drawn into contact therewith and held thereby. This condition is illustrated in FIG. 6. As seen in this figure, the pieces of tape 44 are facing upwardly on the interior volume of the cover 20 to provide the barrier so that no foam can leak through the openings formed along the sew lines. 
     A foaming composition such as a high resilient cold cure urethane foam sold by Inmont under the name Polyurethane Foam is placed inside the mold. The cover portion 52 of the mold is closed and the foam is allowed to react. When the foam reacts, it fills the entire internal volume defined in the cover member with a resilient foam. 
     After the foaming operation is over, the cover portion 52 of the foaming mold 46 is opened and the combined locating member 26, the cover 20 and the foam material produced therewithin by reaction of the foaming composition are removed from the mold. The locating member 26 is then cut off the peripheral edge of the cover member to produce a final cover member which may be used as an automobile seat cushion. 
     There has been disclosed herein a method of producing a covered article and, in particular, a method for producing a covered article which may be used as a seat for an automobile. In view of the teachings of this specification, those skilled in the art will be capable of making modifications of the method of this invention without departing from the true spirit and scope thereof. It is intended that all such modification which fall within the true spirit and scope of this invention be included within the scope of the appended claims.