GB2278082A

GB2278082A - Forming a trim cover assembly

Info

Publication number: GB2278082A
Application number: GB9309417A
Authority: GB
Inventors: Hisaya Tokura
Original assignee: Tachi S Co Ltd
Current assignee: Tachi S Co Ltd
Priority date: 1993-04-26
Filing date: 1993-05-07
Publication date: 1994-11-23
Anticipated expiration: 2013-05-07
Also published as: GB9309417D0; GB2278082B; GB9308878D0

Abstract

A trim cover assembly for an automotive seat is formed by stretching and pressing a top cover layer (1) on a lower die (R; R') by plural upper die elements (21, 22, 22'...) in sequence in the outward direction and symmetrically relative to a central line of the lower die, to thereby place the top cover layer (1) without clearance and slackened area therein, upon the lower die (U"), and then a foam wadding (2a, 2b, 2c, 2d and 2f) and a wadding cover are fixed to the thus-pressed top cover layer (1). Thus, the resulting trim cover assembly is formed with a clear-cut or very distinct pattern of recessed grooves (1a, 1b...) thereon. <IMAGE>

Description

METHOD AND DEVICE FOR FORMING A TRIM COVER ASSEMBLY FOR AUTOMOTIVE SEAT The present invention relates to a method for forming a trim cover assembly for an automotive seat, and a device for carrying out such method.

A known trim cover assembly for an automotive seat comprises a plurality of patterns of recessed grooves (a')(a')(a') formed on its surface for the purpose of improving the outer appearance of the seat, as shown in Figure 1(A). This known trim cover assembly (C) is of a three-lamination type comprising a top cover layer (1) (made of woven fabric, synthetic resin leather, etc), a second layer of foam wadding (2) (preferably a slab urethane foam material), and a third layer of wadding cover (3) (preferably a non-woven fabric).

The three layer materials (1)(2)(3) are locally pressed and welded together by a high frequency welding device as shown in Figure 1(B) to form the illustrated patterns of stripe-like recessed grooves (a')(a')(a').

The formation of such patterns is effected by a conventional method using an upper die (U) and a lower die (R), which consists of the steps of placing the three layers, ie the top cover layer (1), foam wadding (2) and wadding cover (3) on the lower die (R), in that order. The upper die (U) is then lowered to press and weld the three layers (1)(2)(3) at the points corresponding to projected electrode portions (10) ...

to form patterns of recessed grooves (a') ... on the top cover layer (1).

A disadvantage of this known method is that the profile of each pattern (a') is not clear-cut. That is, as seen from Figures 1(A), each resulting pattern (a') does not have clear-cut corners and is able to loosen to produce undesired arcuate corners.

Another solution to this problem, referring now to Figures 1 (C) and 1 (D), has been proposed, which employs another improved high-frequency welding device comprising a flat upper die (U') and a suction-type lower electrode die (R') having a plurality of equidistant projected electrodes (11, 12, 13 ...) as shown in Figure 1(C).

The lower die (R') is formed in a box-like configuration having a hollow therein, having a plurality of suction holes (101 ...) perforated in the upper wall thereof, each of which is defined in the respective sections partitioned by the foregoing plurality of projected electrodes (11, 12, 13 ...), and a tube (32A) connected to a suitable air suction device (not shown).

In this second known technique, the three-layer trim cover assembly to be formed utilizes a plurality of separate foam waddings (2a) (2b) (2c) (2d) (2e) (2f), each being of a clear-cut square shape in section. The top cover layer (1) and wadding cover (3) are the same as those of the first known method described herein above.

The second known technique comprises the steps of firstly placing the top cover layer (1) on the plural projected electrodes (11, 12, 13 ...) of lower die (R'), then forcibly attracting the top cover layer (1) to the lower die (r') as well as to the plural projected electrodes (11, 12, 13 ...) by sucking air through the suction holes (101 ...) through operation of the air suction device. The separate waddings (2a, 2b ...) and wadding cover (3) are then placed in that order, upon the top cover layer (1) thus secured to the lower die (R'), and finally the three layers are subjected to a highfrequency welding, with a pressure plate (P) lowered to press them against the lower one (R'). This approach is more effective in rendering the resulting patterns of recessed grooves in the trim cover assembly clear of distinct, owing to the forcible attraction of the top cover layer (1) to the lower die (R') and the separate waddings (2a, 2b ...).

This second known technique described above is also unable to produce completely clear-cut corners of each pattern produced thereby. This is because clearances (H) are created symmetrically relative to each of the projected electrodes (11, 12 ...), as depicted in Figure 1 (D) despite the top cover layer (1) being drawn to the upper surface of the lower die (R). Consequently, the clearances (H) result in the top cover layer (1) pressing the corners of each separate padding (2a, 2b ...) and making them arcuate, with the result that the four corners of resulting patterns of recessed grooves (see Figure 8 for reference only) dot not present complete clear-cut or distinct corners conforming to those of the rectangular profile of each separate padding (2a, 2b ...), although not clearly shown. This impairs the aesthetic appearance of seat.

In view of the above stated drawbacks, it is a first purpose of the present invention to provide an improved method and device for forming a trim cover assembly, which produce clear-cut or distinct patterns of recessed grooves on the surface thereof.

In accordance with a first aspect of the present invention, there is provided a method for forming a trim cover assembly for an automotive seat, in which said trim cover assembly is of a three-layer lamination type comprising a top cover layer, a foam wadding and a wadding cover, said method comprising the steps of: providing a lower die having a working surface formed with a plurality of projected portions thereon, wherein said plurality of projected portions extend in a longitudinal direction of said lower die in rows which are generally parallel with one another in a width-wise direction of said lower die; providing a plurality of upper die elements which are vertically moveable toward and away from said lower die, and which are arranged in sets, each set comprising one or more die elements; placing said top cover layer upon said lower die; then, lowering, in sequence, one or more of said plurality of upper die elements towards said lower die, in such a manner that they are lowered one set after another set in an outward direction from and symmetrically relative to a central line of said lower die, to thereby press said top cover layer against said working surface of said lower die; thereafter, raising all said plurality of upper die elements thus lowered, from said lower die; placing said foam wadding and said wadding cover, in that order, upon the thus-pressed top cover layer on said lower die; lowering and pressing a pressure plate against said top cover layer, foam wadding and wadding cover on said lower die, so that they are fixed together integrally to produce the trim cover assembly, whereby patterns of recessed grooves are created in a surface of said trim cover assembly.

Accordingly, the top cover layer is pressed initially at its central area, creating a first recessed groove pattern without any clearance, after which, the remaining area of top cover layer is subject to progressive stretching in the outward direction from and symmetrically relative to the central point by the sequential pressing operations of the plurality of upper die elements at every symmetrical pair of projected portions of lower die. Thus, the resulting trim cover assembly is formed with a clear-cut or more distinct pattern of recessed grooves thereon.

Preferably, said lower die and said pressure plate are formed as electrode means of a high-frequency welding device, and wherein said top cover layer, foam wadding and wadding cover are welded together integrally under a high frequency.

Advantageously said method further includes the step of applying an adhesive to the whole surface of said top cover layer which has been pressed by said plurality of projected portions; said plurality of projected portions including a central projected portion which is disposed at a central longitudinal line in said lower die; an upper die assembly means including a plurality of upper die elements which are moveable vertically towards and away from said lower die means, wherein, in said plurality of upper die elements, there is a central upper die element disposed centrally thereof, said central upper die element being provided with a recessed part into which said central projected portion is to be engaged, and other remaining upper elements constitute plural symmetrical sets in relation to said central upper die element, with such an arrangement that said central upper die element will be lowered firstly towards said lower die, bringing said recessed part thereof into engagement with said central projected portion of said lower die, and then said plural symmetrical sets of other upper die elements will be lowered in sequence, one after another, toward said lower die, so as to sandwich the respective projected portions other than said central projected portion in said lower die; wherein said top cover layer is placed on said working surface of said lower die, and then the upper die elements are pressed upon said lower die, so that said top cover layer, foam wadding and wadding cover are bonded together integrally.

Preferably, the foam wadding comprises a plurality of separate foam wadding pieces, and during said step of placing said foam wadding and wadding cover on said pressed top cover layer on said lower die, each of said separate foam wadding pieces is fitted to respective portions of said top cover layer which have been defined at intervals among said projected portions on said lower die.

According to a second aspect of the invention there is provided a device for forming a trim cover assembly for an automotive seat, in which said trim cover assembly is of a three-layer lamination type comprising a top cover layer, a foam wadding and a wadding cover, said device comprising: a lower die means having a working surface formed with a plurality of projected portions thereon, wherein said plurality of projected portions extend in a longitudinal direction of said lower die and are arranged in rows which are generally in parallel with one another in a width-wise direction of said lower die, such that by said sequential lowering of said plural upper die elements, said top cover layer is caused to lie in close contact upon said working surface of said lower die as well as said plurality of projected portions thereon; and a pressing means for pressing said foam wadding and wadding cover against said top cover layer thus pressed on said lower die, so as to fix them all integrally together.

Advantageously said upper die assembly includes a cylinder means for initially lowering said central upper die element towards said lower die, and then causing said sequential lowering of said other symmetrical sets of upper die elements toward said lower die.

Preferably said lower die means and said pressing means are a part of a high-frequency welding device.

The invention will now be further described by way of example only with reference to the accompanying drawings in which: Figure 1(A) is a partly broken perspective view of a trim cover assembly formed by a first conventional method; Figure 1(B) is a schematic sectional view showing a first conventional device and method for forming the trim cover assembly; Figure 1(C) is a schematic sectional view showing a second conventional device and method; Figure 1(D) is a partly enlarged view of the part (A) in Figure 1(C); Figure 2 is a schematic sectional view showing a principal part of a device according to the second aspect of the present invention; Figure 3 is a schematic perspective view of a whole appearance of the device; Figure 4 is a schematic sectional view explaining a first step of pressing a top cover layer; Figure 5 is a schematic sectional view explaining a second step of pressing the top cover layer; Figure 6 is a schematic sectional view showing the top cover layer to be pressed on the whole; Figure 7 is a schematic sectional view showing steps of fixing a wadding and wadding cover to the pressed top cover layer; and Figure 8 is a partly broken perspective view of resulting trim cover assembly formed according to the present invention.

Referring to Figures 2 and 3, there is illustrated a device for forming a trim cover assembly in accordance with the present invention.

The present invention as embodied in the figures is directed to an improvement upon the second prior art high-frequency welding device as shown in Figures 1(C) and 1(D). Thus, all like designations in Figures 1(C) and 1(D) correspond to all like designations to be given hereinafter and a description on the common parts and members of the prior art and present invention is deleted for simplicity.

Figure 3 shows a complete system for effecting the highfrequency welding to form a trim cover assembly with decorative patterns of recessed grooves thereon, in accordance with the present invention. The system comprises a pair of spaced apart lower dies (R')(R') identical to those of the aforementioned second prior art technique which are moveable forwardly and backwardly with respect to an upper die assembly (U"). A pair of spaced apart pressure plates (P)(P), are each pivoted or hinged at a respective lower base end to a frame of the system, as shown, in a manner rotatable vertically in the arrow direction, and an air suction device (32, 33) to which is connected the tube (32A) of each lower die (R').

Referring to Figure 3, the upper die assembly (U") is disposed at the centre of system, between the right side pressure plate and lower die (P)(R') and the left side pressure plate and the lower die assembly (U") is further supported by four leg frames (61) at a higher level than the two level dies (R')(R'). The upper die assembly (U") comprises a stationary base plate (30), a plurality of moveable upper die elements (21, 22, 22', 23, 23' ...) which pass through the base plate (30) and are moved vertically therethrough by the respective cylinders (C1, C2, C2', C3, C3' ...) guide rods (51) each being provided on those plural upper die elements and penetrating through the base plate (30) in a vertically moveable manner, and a plurality of actuators (CA) provided on the base plate (30), which are adapted to actuate the corresponding cylinders (C1, C2 ...) under a suitable computerized control.

Referring now to Figures 2, 4 and 5 an arrangement of the plural upper die elements (21, 22, 22' ...) and associated cylinders (C1, C2, C2' ...), with respect to the projected electrode portions (11, 12, 12' 13, 13', 14, 14') of the lower die (R') will be described.

As can be seen from Figure 3, the upper die elements are each formed from a rectangular parallolepiped material and the electrode portions are each of elongated plate material, extending from the base plate portion (14a) fixed upon the upper surface of lower die (R').

The central die element (21) is disposed centrally at a point corresponding to the central first electrode portion (11). The central upper die element (21) is formed with a recessed engagement part (21A), into which the central electrode portion (11) is to be engaged.

The die elements are arranged in sets such that a pair of upper die elements (22)(22') form a first set, a pair of upper die elements (23)(23') form a second set a pair of upper die elements (24)(24') form a third set, a pair of upper die elements (25) (25') for a fourth set, and a pair of most outward upper die elements (26)(26') form a fifth set. These five sets of two upper die elements may be moved vertically, independently of one another as is understandable from Figures 4 and 5. Similarly, the cylinders (C1, C2 ...) are arranged in sets in correspondence with the respective associated upper die elements; namely, for instance, the two cylinders (C2)(C2') form a part of the foregoing first set. Hence, the actuators (CA) are operated under a proper control such as to firstly actuate the central cylinder (C1) to lower the central upper die element (21), secondly to actuate a first set of cylinders (C2) (C2') to lower a first set of upper die elements (22)(22'), thirdly to actuate a second set of cylinders (C3) (C3') to lower a second set of upper die elements (23)(23'), in sequence, until a fifth set of upper die elements (26)(26') is lowered.

In this connection, as understandable from Figure 2, it is essential that both central and first set of upper die elements (21)(22)(22') are disposed within the first width (W1 + W2) between the first right and left electrode portions (12) (12').

Also, both second and third sets of upper die elements are arranged such that the left side paired ones (22)(23) thereof are disposed within the left side second width (W2) between the second left side and third left side electrode portions (12) (13), whereas the right side paired ones (22')(23') thereof are disposed within the right side second width (W2) between the second right side and third right side electrode portions (12')(13'). Likewise, further, both fourth and fifth sets of upper die elements are arranged such that the left side paired elements (24) (25) are disposed within the left side third width (W3) between the third left side and fourth left side electrode portions (13)(14), whereas the right side paired elements (24')(25') are disposed within the right side third width (W3') between the third right side and fourth right side electrode portions (13')(14').

In operation, as is understandable from Figure 3, one of the lower dies (R or R') is firstly transferred by a carrier (31), with the top cover layer (1) placed thereon, towards the upper die assembly (U") and positioned therebelow, so that the electrode portions (11, 12 ...) of the lower die are located at a point establishing the above described mating relation with the upper die elements (21, 22, 22' ...). Then, as shown in Figure 4, the central upper die element (21) is lowered by the central cylinder (C1) towards the central electrode portion (11), thus engaging the latter (11) into the recessed part (21A) of the element (21). The top cover layer (1) is pressed at its central vertical line, from both sides, by both upper die element (21) and lower die (R'), so as to produce a central recessed groove pattern (1C) in the top cover layer (1) as seen in Figure 7. Thus, as best seen in Figure 4, the central vertical area of top cover layer (1) is sufficiently brought to a close contact with all the surfaces of central electrode portion (11) and the adjacent area of base plate portion (14a).

Subsequently, as shown in Figure 5, the first set of two upper die elements (22)(22') is lowered to pressingly retain the remaining section of top cover layer within the region between the left side and right side second electrode portions (12)(12'), whereupon the central area of top cover layer (1), occupying about 2/3 the area of the layer (1) is neatly stretched within such region, with the top cover layer (1) in close contact on all the lower corners of the central, second left side and second right side electrode portions (ll)(l2)(12'). The same operations will be carried out with respect to all the remaining upper die elements (23, 23', 24, 24' 25, 25', 26, 26') and electrodes portions (13, 13', 14, 14'), so that most of the area of the top cover layer (1) is retained in a close contact upon the upper die surface of lower die (R') without any slackened area therein. At the completion of this operation, the air suction device (32, 33) is operated to suck air within the lower die (R') in order to forcibly draw the thus retained area of top cover layer (1) to the lower die (R'). This insures a complete uniform securement of such retained area of top cover layer (1) upon the electrode die surface of lower die (R'). Then, all the upper die elements (21, 22, 22') are raised away from the lower die (R'), and the top cover layer (1) lies neatly upon the electrode die surface of lower die (R') as shown in Figure 6. Namely, the top cover layer (1) is bent sinuously by the plurality of electrode projected portions (11, 12, 12', 13, 13', 14, 14') and the plurality of interval sections of base plate portion (14a) defined among those electrode projected portions, thereby defining a plurality of recessed groove pattern portions (1A, 1B, 1C, 1D, 1E, 1F) and a plurality of crest portions (lA', lB', lC', lD', lE', lF') in the top cover layer (1).

Finally, as shown in Figure 7, the separate foam waddings (2a) (2b) (2c) (2d) (2e) (2f) are fitted into the foregoing crest portions (lA')(lB')(lC')(lD')(lE')(lF') of top cover layer (1) secured on the lower die (R'), respectively, after which, the wadding cover (3) is placed over the thus fitted waddings and the pressure electrode plate (P) is rotated downwardly to press together all three layers so that those three layers are subject to a high frequency welding.

The high frequency welding is not limitative in the present invention, and both pressure electrode plate (P) and projected electrode portions (11, 12 ...) may be made of a mere rigid metallic plate, in which case, an adhesive should be applied to the whole surfaces of top cover layer (1) in order that the waddings (2a, 2b ...) may be bonded to the crest portions (IA', 1B' ...) thereof, respectively, and further the wadding cover (3) be bonded at the recessed groove portions (1A, 1B ...) thereof.

Finally, after the welding or bonding process, the pressure plate (P) is raised from the lower die (R'). The trim cover assembly thus formed is then taken out from the lower die (R'), with the result that there is obtained a finished trim cover assembly (C) having a plurality of clear cut patterns (a) of recessed grooves formed therein, as illustrated in Figure 8.

It is to be appreciated that, in accordance with the present invention, the top cover layer (1) begins to be laid on the centre point of the lower die (R'), while a portion of the top cover layer (1) is pressed to the central projected portion (11), thereby creating a first recessed groove pattern (1C) without clearance. The top cover layer (1) is then subject to a progressive stretching in the outward direction from and symmetrically relative to such central point by the sequential pressing operations of the plurality of upper die elements (22, 22' ...) at every symmetrical pair of projected portions (ie (12, 12') i (13, 13') or (14, 14')). In this way, it is effectively possible to not only draw the portions of top cover layer (1) completely into both lower corners of each projected portion (11, 12, 12' ...) but also stretch the top cover layer (1) naturally without creating slackened portions therein.

Accordingly, the top cover layer (1) is formed with a plurality of recessed groove pattern portions (lA, 1B ...) in a completely clear cut manner, thus avoiding the problem of clearances (H) found in the prior art.

For the above purpose, as shown, it is important that each of the projected portions (12, 12' ...) subsequent to the central one (11) is sandwiched between adjoining two upper die elements, to thereby completely draw the corresponding portions of top cover layer (1) into both lower corners of the projected portion. In this respect, preferably, an appropriate slight clearance is given between the lateral side of projected portion (12, 12' ...) and the mating side of upper die element (22, 22' ...) taking into account the thickness of top cover layer (1).

It is noted that the top cover layer (1) is made of a nonpermeable leather material which is suited for the air sucking operation stated above.

While having described the present invention as above, it should be understood that the invention is not limited to the illustrated embodiment, but any other modifications, replacements and additions may be applied thereto structurally without departing from the scope of the appended claims. For example, the air suction device (32, 33) may not be used because of the above described arrangement for contacting the top cover layer (1) closely upon the working surface of lower die (R'). The recessed groove patterns shown may be altered to other possible patterns.

Claims

1. A method for forming a trim cover assembly for an automotive seat, in which said trim cover assembly is of a three layer lamination type comprising a top cover layer, a foam wadding and a wadding cover, said method comprising the steps of: providing a lower die having a working surface formed with a plurality of projected portions thereon, wherein said plurality of projected portions extend in a longitudinal direction of said lower die in rows which are generally parallel with one another in a width-wise direction of said lower die; providing a plurality of upper die elements which are vertically moveable toward and away from said lower die, and which are arranged in sets, each set comprising one or more die elements; placing said top cover layer upon said lower die; then, lowering, in sequence one or more of said plurality of upper die elements towards said lower die, in such a manner that they are lowered one set after another set in an outward direction from and symmetrically relative to a central line of said lower die, to thereby press said top cover layer against said working surface of said lower die; thereafter, raising all said plurality of upper die elements thus lowered, from said lower die; placing said foam wadding and said wadding cover, in that order, upon the thus pressed top cover layer on said lower die; lowering and pressing a pressure plate against said top cover layer, foam wadding and wadding cover on said lower die, so that they are fixed together integrally to produce the trim cover assembly, whereby patterns of recessed grooves are created in a surface of said trim cover assembly.

2. A method as defined in claim 1, wherein said lower die and said pressure plate are formed as electrode means of a high-frequency welding device, and wherein said top cover layer, foam wadding and wadding cover are welded together integrally under a high-frequency.

3. A method as defined in claim 1, wherein said method further includes the step of applying an adhesive to the whole surface of said top cover layer which has been pressed by said plurality of projected portions; said plurality of projected portions including a central projected portion which is disposed at a central longitudinal line in said lower die; an upper die assembly means including a plurality of upper die elements which are moveable vertically towards and away from said lower die means, wherein, in said plurality of upper die elements, there is a central upper die element disposed centrally thereof, said central upper die element being provided with a recessed part into which said central projected portion is to be engaged, and other remaining upper elements constitute plural symmetrical sets in relation to said central upper die element, with such an arrangement that said central upper die element will be lowered firstly towards said lower die, bringing said recessed part thereof into engagement with said central projected portion of said lower die, and then said plural symmetrical sets of other upper die elements will be lowered in sequence, one after another, toward said lower die, such as to sandwich the respective projected portions other than said central projected portion in said lower die; wherein said top cover layer is placed on said working surface of said lower die, and then the upper die elements are pressed upon said lower die, so that said top cover layer, foam wadding and wadding cover are bonded together integrally.

4. A method as defined in claim 1, wherein said foam wadding comprises a plurality of separate foam wadding pieces, and wherein, during said step of placing said foam wadding and wadding cover on said pressed top cover layer on said lower die, each of said separate foam wadding pieces is fitted to respective portions of said top cover layer which have been defined in intervals among said projected portions on said lower die.

5. A device for forming a trim cover assembly for an automotive seat, in which said trim cover assembly is of a three layer lamination type comprising a top cover layer, a foam wadding and a wadding cover, said device comprising: a lower die means having a working surface formed with a plurality of projected portions thereon, wherein said plurality of projected portions extend in a longitudinal direction of said lower die and are arranged in rows which are generally in parallel with one another in a width wise direction of said lower die, such that by said sequential lowering of said plural upper die elements, said top cover layer is caused to lie in close contact upon said working surface of said lower die as well as said plurality of projected portions thereon; and a pressing means for pressing said foam wadding and wadding cover against said top cover layer thus pressed on said lower die, so as to fix them all integrally together.

6. A device as defined in claim 5, wherein said upper die assembly includes a cylinder means for initially lowering said central upper die element towards said lower die, and then causing said sequential lowering of said other symmetrical sets of upper die elements toward said lower die.

7. A device as defined in claim 5, wherein said lower die means and said pressing means are a part of a high-frequency welding device.

8. A method substantially as hereinbefore described with reference to the accompanying figures 2 to 8.

9. A device substantially as hereinbefore described with reference to the accompanying figures 2 to 8.