Substrate convering method and apparatus

#The present invention relates to covering a rigid or semi-rigid substrate with a flexible covering material. The invention is especially adapted for upholstery applications where a rigid or semi-rigid substrate is covered with at least a layer of flexible upholstery and often a layer of flexible cushion or padding material.

#When covering such a substrate, one must not only cover the front and sides of the substrate, but also must wrap the upholstery around to the back side of the substrate. Typically, the marginal edge of the covering material is secured to the back surface of the substrate.

#It is common to perform this covering operation by placing the fabric and any cushioning material over a mold cavity, push the substrate down onto the upholstery and cushion and then push the composite into the mold cavity. Fingers or clamps then slide over the upwardly projecting marginal edge of the upholstery and push it down onto the back side of the substrate. Glue is often applied to the back side of the substrate so that when the upholstery is pushed down over it, it is adhered to it.

#These and other aspects, advantages and features of the invention will be more fully understood and appreciated by reference to the written specification and appended drawings.

#FIG. 1 comprises a perspective view of a mold and mold press made in accordance with the present invention;

#FIG. 2 comprises a cross-sectional view of the mold with a substrate shown in phantom above the mold;

#In the preferred embodiment, mold 10 comprises a body 11 defining a cavity 12 (FIGS. 2-10). A resiliently flexible lip 13 overhangs and generally surrounds cavity 12. A starter recess 14 located above lip 13 and mold cavity 12 helps properly align upholstery layer 1, cushioning layer 2 and substrate 3 in the manner shown in FIG. 5. Press 30 (FIG. 1) includes an injection plunger 34 which pushes rigid or semi-rigid substrate 3 and covering composite comprising a layer of upholstery 1 and a layer of cushioning 2 down into mold cavity 12, past lip 13 (FIGS. 5-7). Sealing plunger 36 is then forced downwardly to seal the marginal edge of upholstery covering 1 against the back side of substrate 3 (FIG. 8). The finished part can then be ejected through the activation of ejection lever 18 and ejection pin 19 in mold 10 (FIG. 11).

#Preferably, the entire main body 11, including overhanging lip 13 of mold 10 is molded of a resiliently flexible elastomeric material. Preferably, a polyurethane elastomer is used. Such materials are used for making flexible molds which can be stripped from parts with undercuts. One suitable material is RENC:C:O-THANE.TM. RP-6400 polyurethane elastomer available from REN Plastics of Lansing, Mich. (a CIBA-GEIGY Company). This material has a Shore A hardness of 40-45 as determined by ASTM Test Method D-2240. Other elastomeric materials somewhat softer or somewhat harder could be used in the broader aspects of the invention, as for example from about 30 to about 75 on the Shore A scale. However, the aforesaid polyurethane elastomer with a Shore A hardness of 40-45 is currently the best mode contemplated for practicing this invention.

#Preferably, mold body 11 is formed onto a steel backing plate 15, around a suitable insert for defining mold cavity 12 and starter cavity recess 14 (FIGS. 2-11). Steel plate 15 has apertures so that a portion of the polyurethane elastomeric resin will flow into the holes and define anchors 11a which help anchor body 11 to steel backing plate 15 (FIG. 11). When the resin has cured, the plug used to form cavity 12 and starter recess 14 ca be peeled out of mold body 11 and mold body 11 and backing plate 15 can be removed from their mold cavity.