A method for making a mattress web, comprising the steps of:
- continuously indexing a first fabric web having a width incrementally to and through a succession of stations in a downstream direction;
- at a first of said stations,
- (i) forming in each respective longitudinally successive increment of said first fabric web a curve that extends fully widthwise of said first fabric web and has a leading side, a trailing side, a bottom interconnecting the leading side to the trailing side, and an upwardly opening mouth defined by the leading side and the trailing side, and
- (ii) introducing a compression coil spring in a relaxed state downwardly through said mouth into said curve and against said bottom;
- at a second of said stations downstream from said first station,
- (iii) supporting said bottom on a substantially horizontal planar surface, and
- (iv) vertically compressing said coil spring downwardly against said bottom while said bottom remains supported on said substantially horizontal planar surface, thereby placing said coil spring in a vertically compressed state and stretchingly transforming said curve into a pocket having a trailing upper surface, a leading upper surface, a trailing face, a leading face parallel to the trailing face, a bottom surface interconnecting and perpendicular to the trailing face and the leading face, and an upwardly extending opening defined by the leading upper surface and the trailing upper surface, whereby said coil spring in said vertically compressed state is located entirely within the pocket and the bottom surface is supported on said substantially horizontal planar surface;
- at a third of said stations downstream from said second station, maintaining said coil spring in said vertically compressed state;
- at a fourth of said stations downstream from said third station,
- (v) removing said coil spring from said vertically compressed state, thereby causing said coil spring to resume a relaxed state, and thereby causing an upper portion of said coil spring to extend upwardly above said upwardly extending opening, and then
- (vi) urging a tool against said coil spring, thereby vertically compressing said coil spring downwardly against said bottom surface while said bottom surface remains located on said substantially horizontal planar surface, and thereby placing said coil spring in a vertically compressed state entirely within said pocket;
- and then
- at a fifth of said stations downstream from said fourth station,
- (vii) while continually urging said tool against said coil spring and thereby maintaining said coil spring in said vertically compressed state entirely within said pocket, continuously feeding a second fabric web incrementally onto said first fabric web and welding a first portion of said second fabric web to the leading upper surface, thereby providing a welded pocket portion, then
- (viii) releasing said tool from said coil spring and conveying said welded pocket portion away downstream from said fifth station while applying a compressive force to said coil spring, thereby bringing the trailing upper surface to said fifth station with said coil spring in a compressed state, and then
- (ix) welding a second portion of said fabric web to the trailing upper surface, thereby capturing said coil spring in said pocket in a compressed state.