VEHICLE SEAT ASSEMBLY WITH POUR-IN-PLACE FOAM BODY

Abstract: A method of manufacturing a portion of a seat is disclosed. A cover member is shaped to a predetermined shape and placed in a foam molding tool into which is injected an expandable liquid foaming material to mold a foam pad which is integrally bonded to the cover member. In the manufacturing of seat backs, the cover member consists of a tubular envelope cover positioned on a cantilever forming tool. Once the foam pad is molded, the cover member is turned inside out to enclose the foam pad with the cover member. The cover is then telescoped over a seat frame. Alternatively, the foam pad can be molded to a shaped fabric sheet, the envelope cover formed by sewing a second cover member to the fabric sheet. A seat cushion is made by shaping a cover member, placing the cover member in a foam molding tool which also holds the seat frame and injecting an expandable liquid foaming material into the mold to mold the foam cushion, bond the cushion to the cover and embed the seat frame in the foam. The edges of the cover are then wrapped around the side of the foam pad and attached to the frame. Alternatively, a side panel can be sewn to the cover and attached to the frame.

Description: This invention relates generally to a method for manufacturing seats, and more particularly to a method for manufacturing vehicle seats wherein seat constructions are required which can be manufactured in large quantities at low costs and with a broad range of styling possibilities. One method for making seats with a foam pad is illustrated in U. S. Patent No. 2,955,972 issued to Wintermute, et al. The method shown in Wintermute uses a vacuum to shape the seat cover and is thereby limited for use with seat covers which are imperforate. The seat produced by Wintermute also has a foam pad which is bonded on all sides to either the cover or base panel. It is an object of this invention to provide a vehicle seat construction which utilizes a foam pad which is formed by a pour-in-place process in which the foam pad is molded onto and integrally bonded to the seat trim cover. An advantage of this invention is lower overall production costs as well as a faster production process. It is a further advantage of this invention to use seat cover materials which are perforate. It is yet another advantage of this invention that the foam pad is only bonded to the load engaging surface of the cover which reduces the wrinkling of the side panels when the seat is loaded. It is a further object of this invention to provide a method for manufacturing seats which enables the construction of seat trim covers that have soft back panels thereby eliminating the need for hard plastic panels, zippers or other fastener/attachments that are cost-incurring items in a seat trim cover, such as a cover for a vehicle seat back. Because the seat trim cover is an integral assembly with a foam pad of the desired configuration enclosed therein, the product lends itself to a broader range of styling possibilities which is an obvious advantage in the field of automobile seating. US-A-4 740 260 discloses our earlier method of making a portion of a seat as defined in the prior art portion of claim 1. The present invention as defined in claim 1 utilised a pour-in-place process to mould the foam pad used in the seat back and the seat cushion. The foam pad moulded by this process conforms to the shape of the seat cover. This avoids difficulties in aligning a pre-shaped foam pad to the shape of the seat cover. This also results in a better fitting foam pad and seat cover, having fewer wrinkles than with a pre-shaped pad. The method of this invention as later described in detail consists generally of the following steps. First, a portion of the seat trim cover is shaped to a predetermined shape. The portion that is shaped is the face of the seat cover that engages the seating load, i.e. the top of the seat cushion and the front of the seat back. This surface is referred to as the "A" surface. The method used to shape the seat trim cover can be used with vinyl, leather or cloth fabric materials which are perforate or imperforate. Additionally, the seat trim cover material is not stretched or thinned out by the shaping process. Second, a foam pad is moulded by a pour-in-place process using an expandable liquid foam material which moulds the foam pad in place on the shaped, load engaging portion of the seat trim cover. The foam pad is thereby integrally bonded to the seat trim cover and moulded ot the predetermined shape of the seat trim cover. In this method, only the load engaging surface of the seat trim cover is bonded to the foam pad. The side faces of the seat trim cover are free to flex, thus reducing or eliminating wrinkles in the seat trim cover when a load is applied to the seat. While a pour-in-place process has been previously proposed for a seat cushion as disclosed in US-A-3 878 277, this is in conjunction with a seat cushion where the base can be left uncovered and not in the unusual circumstances of the present invention where the mould-inplace takes place on the inner surface of an inverted sock-like cover. The seat trim cover used in the method of the invention is an envelope cover, generally tubular in shape having an open end, a closed end, an inner side and an outer side. The envelope cover is turned inside out before shaping the load engaging face of the cover. The foam pad is moulded and bonded onto the inner side of the load engaging face of the envelope cover. The envelope cover is then turned inside out again so the outer side is on the outside to enclose the foam pad and enable the cover to be telescoped over a supporting frame. Further features and advantages of the invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawings, in which:- Figure 1 is a perspective view of a cantilever forming tool illustrating an envelope cover which has been turned inside out, being mounted on the forming tool, in the manufacture of a seat back using the method of the invention. Figure 2 is a perspective view illustrating a second forming tool over the envelope cover mounted on the cantilever forming tool. Figure 3 is a perspective view like Figure 1 illustrating the shaped envelope cover mounted on the cantilever forming tool. Figure 4 is a perspective view illustrating the pour-in-place foam moulding tool telescoped over the cover and cantilever forming tool. Figure 5 is a perspective view illustrating the moulded foam pad bonded to the envelope cover mounted on the cantilever forming tool. Figure 6 is a perspective view illustrating the cover being turned right side out so as to enclose the pad. Figure 7 is a perspective view illustrating the envelope cover and pad assembly. Figure 8 is a sectional view illustrating an alternative embodiment of the seat back with a back panel attached to the cover member. Figure 9 is the same view as Figure 8 after the back panel and seat .cover are turned right side out to enclose the foam pad. Detailed Description of the Drawings One method of making a seat back using the pour-in-place process for the foam pad is shown in Figures 1 to 7. With reference to the drawings, an envelope cover member of this embodiment, indicated generally at 20, is illustrated in Figure 1 in a position in which it is about to be placed on a shaped forming tool member 22 that is cantilever supported on a support structure 24. The envelope cover member 20 is of a generally tubular shape having an open end 26, closed end 28, inner side and an outer side. In the position of the envelope cover 20, shown in Figure 1, the inner side faces outwardly for a purpose to appear presently. The face 29 of cover member 20 is the load engaging or "A" surface of the cover member 20 as will be described below. The forming tool 22 is shaped to provide a desired contour to the load engaging face 29 of the envelope cover 20 and, accordingly, is illustrated by having a plurality of upwardly extending inverted U-shaped projections 34 and headrest section 36. It is to be understood that the forming tool 22 can be substantially any shape desired for the seat back. The envelope cover 20 is telescoped, open end 26 first, over tool 22 to a position in which substantially the entire cover member 20 is supported on the forming tool 22 which is cantilever supported on the support structure 24 to enable the cover member 20 to be telescoped thereover. Shown in Figure 2, a second forming tool 38 is lowered onto the envelope cover 30 so as to form the load engaging face 29 of the cover 30 to the shape of the forming tool 22. The forming tools 22 and 38 are of complementary shape so as to sandwich the cover member 20 therebetween and shape of the envelope cover 20 to the shape of the forming tool 22. Heat and pressure are applied to the tools 22 and 38 to facilitate forming of the envelope cover 20 to the desired shape. Figure 3 shows the envelope cover 20 on forming tool 22 after envelope cover 20 has been shaped. As shown in Figure 4, a form molding tool 40 is then positioned over the envelope cover 20. Foam molding tool is used for molding a foam pad by pouring-in-place an expandable liquid foaming material. The liquid foaming material is injected into the foam molding tool 40 through opening 44. This molding operation is performed in such a manner that foam pad 46 is molded and integrally bonded to the inner side of the load engaging face 29 of envelope cover member 20 and formed to the shaped contour of load engaging face 29. The foam pad 46 is shown in Figure 5 molded and bonded to the inner side of load engaging face 29 of cover member 20. After the foam pad has cured, the assembly consisting of the envelope cover 20 and foam pad 46 is moved lengthwise off the cantilever supported forming tool 22. The envelope cover 20 is then manipulated as shown in Figure 6 such that the outer side of the envelope cover 20 is on the outside and the foam pad 46 is enclosed in the envelope cover 20. The resulting assembly shown in Figure 7 can then be telescoped over a supporting seatback frame. By making a seat back in this manner, the envelope cover member 20 is bonded to the foam pad only on the load engaging "A" surface 29 of the envelope cover member 20. In other words, only the portion of the envelope cover member 20 which engages the seating load is bonded to the foam pad 46. This reduces or eliminates the wrinkling of the sides of envelope cover member 20 which can occur during loading of the seat if the side faces of the cover member 20 are also bonded to the foam pad. The seat assembly produced by this method can be readily manufactured while still allowing a broad range of styling possibilities since the construction of the forming tools 22 and 38 controls the style that is imparted to the envelope cover 20 and the foam pad 46. The structure of the forming tools 22 and 38 can readily be varied to achieve a desired styling result. An alternative method for making the seat back is shown in Figures 8 and 9. In this method, a cover member 80 is used instead of the envelope cover member 20 shown in Figure 1. Like envelope cover 20, cover 80 has inner and outer sides. Cover member 80 is first formed to a predetermined shape. The shaped cover member 80 is placed in a pour-in-place foam mold where a foam pad 82 is formed by pouring an expandable liquid foam into the mold, thereby molding a foam pad 82 which is bonded to the inner side of cover member 80. A back panel member 84 is attached to edges of the outer side of cover member 80 thereby forming an envelope having an open end. Back panel 84 is attached to cover member 80 by sewing or other methods known in the art. The envelope is then manipulated in such a manner that foam pad 82 is inside the envelope formed by cover member 80 and back panel 84. A cross section of the enclosed foam paid is shown in Figure 19. The resulting assembly can then be telescoped over a supporting seatback frame. There are several benefits to the use of the pour-in-place process to mold the foam pad instead of using a pre-shaped pad. The overall production cost is lower, eliminating the step of attaching a foam pad to the cover. In addition, there are no difficulties associated with aligning a pre-shaped pad with the shape cover thereby resulting in a better fitting cover and a faster production process.

Claims: A method of manufacturing at least a portion of a seat having a predetermined shape, said seat including a supporting frame, a foam pad mounted on said frame, and an envelope cover member over said foam pad, said member being generally tubular shape having an open end and inner and outer sides and a seating load engaging portion, comprising the steps of: turning said envelope cover member inside out so that said inner side is on the outside of said envelope cover member; telescoping said cover member onto a forming tool; shaping the load engaging portion of said envelope cover member to said predetermined shape; providing a foam pad adhered to the shaped load engaging portion of the envelope cover member; manipulating said envelope cover member so that said outer side is on the outside of said envelope cover member with said foam pad enclosed within the envelope cover member and telescoping said envelope cover member with said foam pad therein open end first over and onto said supporting frame, characterised in that said foam pad is formed by being moulded in place upon said load engaging portion of said envelope cover member by pouring-in-place an expandable liquid foaming material in such a manner that said foam pad is bonded to said load engaging portion and conformed in shape to the shape of said load engaging portion of said envelope cover. A method according to claim 1, wherein said shaping is performed by application of heat and pressure to said load engaging portion of said envelope cover member.

Inventors: WITZKE, DUANE WILLIAM
Applicants: HOOVER UNIVERSAL, INC.
Application year: 1989
Main classification: B29C67
IPC codes: B68G7, B29L31, B60N2, B29C44, B29C39, B29K105