A comfort layer for a bedding or seating product has slow-acting pockets characterized by the individual springs of the comfort layer being pocketed with either semi-impermeable or impermeable fabric. Each seam joining opposed plies of fabric around each of the coil springs of the comfort layer may be segmented, allowing air to flow between the segments, thereby increasing the luxury “feel” of the comfort layer. The method of making the comfort layer includes compressing the springs and creating pockets with a welding horn and an anvil.

A mechanism (300) for transferring coil springs from a coil winding device (110) to a conveyor belt (210) of a pocketed coil assembly machine comprises a magnetic lift platform (310) for engaging a coil spring (10) before being released at an output of the coil winding device (110). Further, the mechanism comprises a drive mechanism (315) for moving the lift platform (310) between the output of the coil winding device (110) and the conveyor belt (210).

A method to manufacture a steel wire spring core for a mattress or for seating is described, which comprises the steps of providing a carrier comprising steel wire; repeatedly cold coiling a steel wire spring from steel wire taken from the carrier; and connecting a series of the coiled steel wire springs to each other. The steel wire has a diameter d between 0.8 and 4.5 mm; and has a drawn pearlitic microstructure. The steel wire comprises a steel alloy having a carbon content between 0.35 wt % and 0.85 wt %. The steel wire on the carrier has a ratio—expressed as a percentage—of the yield strength R.sub.po 2 (in MPa) over the tensile strength R.sub.m (in MPa) higher than 85%.

A method to manufacture a steel wire spring core for a mattress or for seating is described, which comprises the steps of providing a carrier comprising steel wire; repeatedly cold coiling a steel wire spring from steel wire taken from the carrier; and connecting a series of the coiled steel wire springs to each other. The steel wire has a diameter d between 0.8 and 4.5 mm; and has a drawn pearlitic microstructure. The steel wire comprises a steel alloy having a carbon content between 0.35 wt % and 0.85 wt %. The steel wire on the carrier has a ratio—expressed as a percentage—of the yield strength R.sub.po 2 (in MPa) over the tensile strength R.sub.m (in MPa) higher than 85%.

Apparatus for forming a pocketed spring unit, comprising a plurality of strings of pocketed springs and at least one cover sheet, comprises welding tools for welding together the pocketing material and the sheet. One of the welding tools is provided with a cutter for cutting the pocket prior to welding. The tool travels in the direction of Arrow A1, so that the cutter penetrates the pocketing material substantially centrally at the circular proximal end face of the pocket. Once inside the pocket, the tool moves axially through the centre of the spring until it reaches the distal end face of the pocket. Before the end face is reached, the piercing member becomes retracted in the direction of Arrow A2, so that the blade does not pierce the distal end face of the pocket.

Apparatus for forming a pocketed spring unit, comprising a plurality of strings of pocketed springs and at least one cover sheet, comprises welding tools for welding together the pocketing material and the sheet. One of the welding tools is provided with a cutter for cutting the pocket prior to welding. The tool travels in the direction of Arrow A1, so that the cutter penetrates the pocketing material substantially centrally at the circular proximal end face of the pocket. Once inside the pocket, the tool moves axially through the centre of the spring until it reaches the distal end face of the pocket. Before the end face is reached, the piercing member becomes retracted in the direction of Arrow A2, so that the blade does not pierce the distal end face of the pocket.

A mechanism for inserting coil springs (10) produced by multiple coil winding devices of a pocketed coil assembly machine (100) between fabrics (21, 22) for forming pockets enclosing the coil springs (10) is provided. The mechanism comprises belt conveyor mechanisms (200) with multiple parallel conveyor belts, which may be individually controlled. Each of the conveyor belts is associated with a respective one of the coil winding devices and is configured to receive coil springs (10) produced by the respective coil winding device. The mechanism further comprises a push mechanism (420) configured to push the coil springs (10) arranged on the conveyor belts, in a direction transversal to a conveying direction of the conveyor belts, between the fabrics and into a welding stage (500) of the pocketed spring assembly machine (100).

A mechanism for inserting coil springs (10) produced by multiple coil winding devices of a pocketed coil assembly machine (100) between fabrics (21, 22) for forming pockets enclosing the coil springs (10) is provided. The mechanism comprises belt conveyor mechanisms (200) with multiple parallel conveyor belts, which may be individually controlled. Each of the conveyor belts is associated with a respective one of the coil winding devices and is configured to receive coil springs (10) produced by the respective coil winding device. The mechanism further comprises a push mechanism (420) configured to push the coil springs (10) arranged on the conveyor belts, in a direction transversal to a conveying direction of the conveyor belts, between the fabrics and into a welding stage (500) of the pocketed spring assembly machine (100).

A pocketed spring assembly comprises a plurality of parallel strings of individually pocketed springs. A dimensionally stabilizing substrate is secured to at least some of the strings on one of the top and bottom surfaces of the strings. A scrim sheet is secured to at least some of the strings on an opposed surface of the strings to maintain the positions of the strings. The dimensionally stabilizing substrate is laterally rigid enough to maintain length and width dimensions of the coil spring assembly. However, the dimensionally stabilizing substrate is flexible enough to allow the pocketed spring assembly to be roll packed for shipping.

A pocketed spring assembly comprises a plurality of parallel strings of individually pocketed springs. A dimensionally stabilizing substrate is secured to at least some of the strings on one of the top and bottom surfaces of the strings. A scrim sheet is secured to at least some of the strings on an opposed surface of the strings to maintain the positions of the strings. The dimensionally stabilizing substrate is laterally rigid enough to maintain length and width dimensions of the coil spring assembly. However, the dimensionally stabilizing substrate is flexible enough to allow the pocketed spring assembly to be roll packed for shipping.