GB2337694A

GB2337694A - A headrest

Info

Publication number: GB2337694A
Application number: GB9811494A
Authority: GB
Inventors: Yoshiyuki Takei
Original assignee: Tachi S Co Ltd
Current assignee: Tachi S Co Ltd
Priority date: 1998-05-28
Filing date: 1998-05-29
Publication date: 1999-12-01
Anticipated expiration: 2018-05-29
Also published as: CA2238853C; GB9811494D0; GB2337694B; FR2780355B1; FR2780355A1; DE19827658B4; CA2238853A1; DE19827658A1

Abstract

A headrest comprising: a substantially doughnut-like three-dimensional trim cover assembly 1 having an annular inner conduit and an opening 10 defined in an external wall thereof by an interiorly extending surface, said trim cover assembly being a laminated structure comprising at least two layers which include a top cover layer and an elastic foam wadding layer; a substantially U-shaped headrest frame 2 comprising a pair of stay portions 21 for mounting on an automotive seat, said headrest frame capable of being disposed in and along the annular inner conduit of said trim cover assembly with said stay portions projecting from said opening thereof; and a sealing frame 3 for connecting said stay portions and for closing and sealing said opening, wherein said sealing frame comprises a surface 31 capable of sealably engaging said interiorly extending surface defining the opening of said trim cover assembly. Liquid foaming material is injected into the annular inner conduit via hole 12, said material is prevented from leaking out by sealing frame 3.

Description

HEADREST 2337694 The present invention relates to a headrest for use on an

automotive seat and to a foaming process for forming said headrest.

In forming a doughnut-like or annular headrest for use on an automotive seat, a known foaming process includes a step that requires inserting a substantially annular shaped headrest frame with headrest stays into and along the annular hollow inside of a preformed three-dimensional, doughnut-like trim cover assembly. A liquid foaming based material is subsequently injected in the trim cover assembly and cured therein to produce a foamed doughnut-like headrest unit with headrest stays projecting therefrom. One problem associated with this process is the difficulty of placing the annular headrest frame in the preformed doughnut-like trim cover assembly prior to foaming.

Solutions to this problem have been disclosed in Japanese laid open patent publication nos. 62-257818 and g271425, and in Japanese granted publication no. 4-401818. These commonly suggest that an inverted substantially Ushaped headrest frame with headrest stays should be inserted in the preformed doughnut-like trim cover assembly. A connecting frame may then be connected between two side frame sections of the headrest frame to provide an annular frame extending in and along the doughnut-like trim cover assembly. Thereafter, foaming is effected to create a foam padding integrally with the frame and trim cover assembly in order to obtain a doughnut-like headrest. However, this solution has the disadvantage that the connecting frame cannot be quickly and precisely assembled with the headrest frame. Since an operator is unable to visually locate the connecting point between the connecting and headrest frames located in the trim cover assembly, he must connect the two frames within the trim cover assembly by touch and feel alone.

To overcome this disadvantage, the connecting frame may be connected to the headrest frame outside the trim cover assembly (see, for example, Japanese granted utility model publication no. 731724). In this disclosure, a plate-like connecting frame is provided which has a slit formed therein. During assembly, a substantially U-shaped headrest frame is inserted into an opening of the doughnut-like trim cover assembly whilst two headrest stay sections of the frame project outwardly therefrom. Thereafter, the plate like connecting frame is connected between the two projected headrest stay sections, whilst the ends of the opening of the trim cover assembly are inserted into and through the slit of the connecting frame. In this way, the connecting frame may be easily accessed and connected to the headrest frame, externally of the trim cover assembly in order to provide an annular framework in conformity with the doughnut-like trim cover assembly and also to close the opening of the trim cover assembly. However, this method suffers the disadvantage that the slit of the connecting frame is rather narrow with a view to preventing leakage of the liquid foaming base material from between the slit and the ends of the opening. As a result, it is troublesome and time consuming for a worker to squeeze and insert the ends of the opening into such a narrow slit during assembly. Furthermore, the insertion may be rather unreliable and liquid foaming base material injected into the trim cover assembly may invade any unsealed areas between the connecting frame and ends of the opening. This undesirably leads to uneven or irregular regions in the outer surface of the resulting headrest thereby impairing the aesthetic appearance.

The present invention seeks to provide an improved doughnut-like headrest for use on an automotive seat and a foaming method for forming the headrest easily and quickly, whilst preventing leakage of liquid foaming based material therefrom.

Thus viewed from one aspect the present invention provides a headrest unit comprising:

a substantially doughnut-like three-dimensional trim cover assembly having an annular inner conduit and an opening defined in an external wall thereof by an interiorly extending surface, said trim cover assembly being a laminated structure comprising at least two layers which include a top cover layer and an elastic foam wadding layer; a substantially U-shaped headrest frame comprising a pair of stay portions for mounting on an automotive seat, said headrest frame capable of being disposed in and along the annular inner conduit of said trim cover assembly with said stay portions projecting from said opening thereof; and a sealing frame for connecting said stay portions and for closing and sealing said opening, wherein said sealing frame comprises a surface capable of sealably engaging said interiorly extending surface defining the opening of said trim cover assembly.

In a preferred embodiment, the sealing frame comprises a groove whose surface is capable of sealably engaging the interiorly extending surface defining the opening of the trim cover assembly.

In a preferred embodiment, the headrest comprises a foam padding within the trim cover assembly obtainable by a foaming process. In manufacturing a headrest of this type, liquid foaming based material is injected into and cured within the trim cover assembly containing the substantially Ushaped headrest frame. The interiorly extending surface defining the opening of the trim cover assembly fits in the groove of the sealing frame to substantially prevent the liquid foaming based material from leaking through the opening during foaming.

The interiorly extending surface defining the opening of the trim cover assembly is fitted in sealable engagement with the groove of the sealing frame to provide a dual sealing effect whereby the surface defining the opening in the trim cover assembly is biasingly contacted with the surface of the groove due to the elastic repercussive property of the foam wadding layer of the trim cover assembly. Furthermore, the same surface is biased to contact with one wall of the groove by the increased mass of the foam cushion padding formed during foaming. Thus, during the foaming process, this dual sealing effect serves to prevent leakage of the liquid foaming based material through the opening. Moreover, a worker may easily connect the sealing frame to the stay portions of the headrest frame from the outside In one embodiment of the present invention, holes may be formed in the sealing frame to receive.the stay portions. This allows easy connection of the sealing frame with the headrest frame at a predetermined point to give a robust frame structure. Preferably, an elastic tubular sealing member may be provided on each of the stay portions so that the holes of the sealing frame are secured about the respective tubular sealing member to seal any minute clearance therebetween. This provides added protection against any possible leakage of liquid based foaming material during foaming.

The present invention will now be illustrated in preferred embodiments with reference to the accompanying figures in which:

Fig. 1 is an exploded schematic perspective view showing an incomplete headrest unit which is to be subjected to a foaming process in accordance with the present invention; Fig. 2 is a front view of a sealing frame, Fig. 3 is a sectional view taken along the line III-III in Fig. 2; Fig. 4 is a diagram illustrating a process of assembling the incomplete headrest unit, in which the sealing frame is about to be connected with two stay headrest frame; Fig. 5 is a perspective view of a resulting incomplete headrest unit; Fig. 6 is a sectional view of an alternative type of sealing frame; Fig. 7 is a schematic sectional view showing the step in which the incomplete headrest unit is placed in a foaming die device, and also showing how foaming is effected; Fig. 8 is a schematic longitudinally sectional view of a resulting foamed headrest wherein a first type of sealing frame is used; and Fig. 9 is a schematic longitudinally sectional view of an alternative resulting foamed headrest wherein a second type of sealing frame is used.

Referring to Figs. 1 to 9, there are illustrated embodiments of the headrest of the present invention. The headrest is of the type having a substantially doughnut-like or annular configuration for use on an automotive seat (not shown).

Fig. 1 shows an incomplete headrest unit (HU) prior to being subjected to a foaming process. As illustrated in the broken perspective, the unit (HU) basically comprises:

a preformed doughnut-like or substantially annular trim cover assembly (1) having an elongated opening (10); an inverted substantially U-shaped headrest frame provided with a locating means (at 21A); and a plate-like sealing frame (3).

As can be seen from Fig. 1 in conjunction with Figs. 7, 8 and 9, the trim cover assembly (1) itself may preferably be a laminated structure having at least two layers and portions of the comprising a top cover layer (1a) and a wadding layer (1b) of slab urethane foam material. This ensures a certain elasticity and rigidity which are important factors for the action of the elongated opening (10). The top cover layer (1a) may be formed from a woven or non-woven fabric material or a synthetic resin leather material.

The trim cover assembly (1) may be preformed by sewing together several separate laminated structure into cover sections of a two-layer the illustrated three-dimensional doughnut or annular shape defining a through-hole (1A). The external wall (1B) of the trim cover assembly (1) is formed with an elongated opening (10) and also with an injection hole (12). The injection hole (12) is adapted to allow insertion of an injection nozzle (see 12 in Fig. 7) so that a liquid foaming base material may be injected into the trim cover assembly (1). In the illustrated embodiment, the elongated opening (10) is defined by a pair of longitudinal surfaces (10A)(10B) and a pair of substantially curved side surfaces (1OR)(1OR). These surfaces define an opening sufficient for the sealing frame (3) to be passed therethrough and smoothly placed in and along the annular inner hollow of trim cover assembly (1).

The sealing frame (3) is of an elongated plate-like configuration having a pair of spaced-apart holes (30) and a peripheral engagement groove (31). The pair of holes (30) are adapted to receive stay portions (21) of the headrest frame (2). The holes (30) are typically slightly greater in diameter than the stay portions (21) to allow smooth passage of the sealing frame (3) along the stay portions (21) until the two holes (30) are frictionally retained about a tubular sealing member (2A).

As shown in Figs. 2 and 3, the groove (31) represents a substantially rectangular recess which conforms substantially in shape to the surfaces (10A, 10B, IOR) defining the elongated opening (10). Thus the groove (31) has a pair of longitudinal surfaces (31B)(31B) for receiving the respective two longitudinal surfaces (10A)(10B) defining elongated opening (10), and a pair of substantially curved side surfaces (31A)(31A) for receiving the respective two side surfcaes (1OR)(1OR) defining the remainder of the opening (10). Outward and inward walls (32)(33) of the frame (3) are defined on opposite sides of longitudinal surfaces (31A, 31B). It is important for sealing purposes that the width of the groove (31) be equal to or slightly greater than the total thickness of the twolayer lamination (la, lb) and that both longitudinal and side surfaces (31B)(31A) of the groove (31) be slightly larger than the elongated opening (10). Preferably, the sealing frame (3) may be formed from a rigid and hard synthetic resin material, such as polypropylene.

The headrest frame (2) in Figure 1 is formed by bending a metallic tube or rod into a substantially U-shaped configuration having a substantially semi-circular head support portion (20) and a pair of stay portions (21) adapted to be mounted on the seat back of a automotive seat (not shown). Each of the two stay portions (21) is provided with a pair of location projections (21A) as a means for limiting and locating the sealing frame (3) at a given position relative to the elongated opening (10) of the trim cover assembly (1). This allows a user to readily locate the frame (3) at the stay portions (21) of headrest frame (2) and also to determine an appropriate proportion of the semi-circular head support portion (20) to be located within the annular inner hollow of the trim cover assembly (1) to allow the user direct engagement of the surfaces (10A, 10B, 1OR) defining the opening (10) in the groove (31). For this purpose, the location projections (21A) extending integrally from the respective opposite sides of one of the stay portions (21) are disposed at a predetermined point on the stay portions (21) near to the juncture between the substantially semicircular head support portion (20) and stay sections (21).

A pair of tubular sealing members (2A) are secured about the stay sections (21) of headrest frame (2) and are adapted to fit in sealable engagement in the holes (30) of the sealing frame (3). The purpose of the sealing members (2A) is not only to retain the sealing frame (3) at a predetermined position defined by the location projections (21A) but also to seal any minute clearance between the stay section (21) and hole (30) against possible leakage of a liquid base foaming material therethrough. The tubular sealing members (2A) may preferably be formed from a rubber tubular material or other suitable elastic material such as an elastic synthetic resin material which serves to strongly adhere to the stay portion (21). As shown in Fig. 1, each of the sealing members (2A) is secured on the stay portion (21) at a point adjoining the location projections (21A), so that the sealing frame (3) may be secured by those sealing members at a predetermined point where the elongated hole (10) of trim cover assembly (1) may easily and quickly be sealably engaged in the groove (31) of frame (3).

In a first step of preparing the headrest of the invention, the headrest frame (2) is inserted via the elongated opening (10) into the doughnutlike trim cover assembly (1) by first inserting one of the two stay portions (21) of headrest frame (2) in the annular inner hollow trim cover assembly (1) so that the headrest frame (2) is circulated within the trim cover assembly (1). Thereafter, the whole of the headrest frame (2) is adjustably placed in position within the trim cover assembly (2) with the stay portions (21) projecting outwardly from the elongated opening (10) (see Fig. 4). At this point, a user may easily locate the headrest frame (2) and its two stay portions (21) relative to the opening (10) because the location projections (21A) and tubular sealing members (2A) are visible at the opening (10). By allowing the two stay portions (21) to pass through the holes (30), the user slides the sealing frame (3) on the two stay portions (21) of headrest frame (2) until the holes (30) ride on and about the two sealing tubular members (2A). Furthermore, the user may continue to forcibly slide the sealing frame (3) until the tubular sealing members (2A) are completely sealed and secured in the respective holes (30) and the inner wall (33) of the frame (3) contacts the location projections (21A). In that way, the sealing frame (3) is now set in position between the substantially semi-circular head support portion (20) and two stay portions (21) of headrest frame (2). A user may then widen the elongated opening (10) with respect to the sealing frame (3) and engage its surfaces (10A, 10B, 1OR) in and along the peripheral engagement groove (31) of the frame (3), whereupon an incomplete headrest unit (HU) i assembled as shown in Fig. 5.

With reference to Fig. 7, the incomplete headrest unit (HU) is then placed between upper and lower dies (UD) (LD) of a known type of foaming die device which has die surfaces substantially contoured along the outer shape of the aboveassembled incomplete headrest unit (HU). An injection nozzle (N) is inserted into the inside of trim cover assembly (1) via the injection hole (12) and an appropriate amount of a liquid foaming base material (4L) is injected into the trim cover assembly (1). The liquid foaming base material (4L) is then cured to subject the whole incomplete headrest unit (HU) to foaming. A foam padding (4) is formed which fills the trim cover assembly (1) integrally together with the headrest frame (2) and sealing frame (3) (see Figs. 8 and 9) thereby producing a doughnut-like headrest (HR). During this foaming process, it will be appreciated that the surfaces (10A, 10B, 1OR) defining the elongated opening (10) are biasingly abutted against and along the groove bottoms (31A, 31B) of sealing frame (3) due to the elastic -10 repercussive property of the foam wadding layer (1b) of the trim cover assembly (1). In addition, the increasing elastic mass of foamed base material (4L) causes the peripheral area of opening (10) to closely contact the outward wall side (32) of groove (31) of sealing frame (3) causing a dual sealing effect between the frame (3) and opening (10) to prevent leakage of the liquid foaming base material (4L) therethrough.

Fig. 6 shows an alternative embodiment of the sealing frame (3) in which a small inward wall (33) is formed relative to the outward wall (32) by simply cutting off the peripheral end region of the corresponding inward wall of the above-described first embodiment of frame (3). This arrangement facilitates the ease with which a worker can engage the opening edges (10A, 10B, 1OR) of trim cover assembly (1) in the groove (31) of sealing frame (3). In other words the user need not widen the opening (10) to receive the frame to the extent required in the first embodiment. Subsequent thereto, foaming is effected as previously stated using the same foaming die device as shown in Fig. 7. Fig. 9 shows a resultant doughnut-like headrest (HR) in which the second embodiment of the sealing frame (3) is used. In this case, the same dual sealing effect is realized between the frame (3) and opening (10) thereby preventing leakage of the liquid foaming base material (4L) therethrough.

In accordance with the present invention, both frames (2) and (3) may be quickly assembled together at a given connecting point (21A). The sealing frame (3) may be easily received in the opening (10) to sealingly close the latter. Further, the sealing frame (3) is connected with the headrest frame (2) via the two holes (30) which advantageously allows a worker to ensure positive connection between the two frames (3)(2) easily and rapidly whilst providing a reinforcement to the headrest frame (2).

Moreover, in contrast to known headrests, the connecting frame (3) per se has an outward wall (32) exposed externally of the trim cover assembly (1) which serves to prevent invasion of liquid foaming base material (4L) and cover the peripheral region of the opening (10) in which invasion might occur. Hence any uneven spots of invaded cured foaming material may be concealed.

Claims

CLAIMS:

1. A headrest comprising: a substantially doughnut-like three-dimensional trim cover assembly having an annular inner conduit and an opening defined in an external wall thereof by an interiorly extending surface, said trim cover assembly being a laminated structure comprising at least two layers which include a top cover layer and an elastic foam wadding layer; a substantially U-shaped headrest frame comprising a pair of stay portions for mounting on an automotive seat, said headrest frame capable of being disposed in and along the annular inner conduit of said trim cover assembly with said stay portions projecting from said opening thereof; and a sealing frame for connecting said stay portions and for closing and sealing said opening, wherein said sealing frame comprises a surface capable of sealably engaging said interiorly extending surface defining the opening of said trim cover assembly.

2. A headrest as claimed in claim 1 comprising a foam padding within the doughnut-like three-dimensional trim cover assembly obtainable by a foaming process.

3. A headrest as claimed in claim 1 or 2 wherein said sealing frame comprises a groove whose surface is capable of sealably engaging the interiorly extending surface defining the opening of the trim cover assembly.

4. A headrest as claimed in claim 3 wherein said sealing frame is a platelike structure having a groove along a peripheral end and wherein said interiorly extending surface defining said opening is sealably engaged in and along said groove whereby said surface is biasingly engaged in the groove due to the elastic repercussive property of said foam wadding layer of the trim cover assembly.

5. A headrest as claimed in claim 4 wherein said Plate-like sealing frame is formed from a hard synthetic resin material.

6. A headrest as claimed in claim 4 or 5 wherein said groove has a surfaces greater in size relative to said opening so that said interiorly extending surface defining said opening is biased to a closed contact with said bottom of the groove due to said elastic repercussive property associated with the trim cover assembly.

7. A headrest as claimed in Claim 4 to 6 wherein said groove has a width equal to or slightly greater than the thickness of said trim cover assembly.

8. A headrest as claimed in any preceding claim comprising a locating means for limiting and locating said sealing frame at a predetermined point on said stay portions with respect to said opening of said trim cover assembly.

9. A headrest as claimed in claim 8, wherein said locating means comprises at least one locating projection formed integrally on said stay portions.

10. A headrest as claimed in any preceding claim wherein said substantially "U"' shaped headrest frame is obtainable by bending a metallic tubular or rod material such as to define therein a substantially semi-circular head support portion and a pair of stay portions, and wherein said substantially semi-circular head support portion is disposed within the annular inner conduit of said doughnutlike trim cover assembly, with said pair of stay portions projecting through said opening and sealing frame to the outside of the headrest.

11. A headrest as claimed in any preceding claim 1 wherein said sealing frame means includes a pair of holes formed therein, and wherein said sealing frame is connected between said stay portions such that said pair of stay portions pass through said pair of holes.

12. A headrest as claimed in claim 11 wherein an elastic tubular sealing member is provided on each of said stay portions such as to seal a clearance between said pair of holes of said sealing frame and said stay portions.

13. A headrest as claimed in claim 8 comprising an elastic tubular sealing member which is provided on each of said stay portions adjacent to said predetermined point such as to seal a clearance between said pair of holes of said sealing frame and said stay portions.

14. A headrest as claimed in claim 1 wherein said sealing frame comprises a groove whose surface defines a substantially H-shaped cross-section.

is. A headrest as claimed in claim 14 wherein the inner wall of said Hshaped groove is shorter than the outward wall of H-shaped said groove.

16. A method for manufacturing a headrest comprising a substantially doughnut-like three-dimensional trim cover assembly having an annular inner conduit and an opening defined in an external wall thereof by an interiorly extending surface, said trim cover assembly being a laminated structure comprising at least two layers which include a top cover layer and an elastic foam wadding layer, said comprising the steps of: inserting an inverted substantially U-shaped headrest frame comprising a pair of stay portions in and along the annular inner conduit of said trim cover assembly with said stay portions projecting from said opening thereof; sliding a sealing frame comprising a surface capable of sealably engaging said interiorly extending surface defining the opening of said trim cover assembly onto said stay portions whereby to close and seal said opening.

17. A method as claimed in claim 16 comprising: injecting liquid foaming material into said headrest unit; forming foam padding.