Method and apparatus for shredding foam

Claim 2

A method according to claim 2 wherein the step of recycling comprises the steps of positioning the rejected particles on a surface substantially concentric with and spaced from the periphery of the tearing surfaces, rotating the tearing surfaces at a sufficient speed to cause removal of the particles in the direction of rotation of the tearing surfaces, and guiding the removed particles towards the opposing tearing surfaces for reshredding and size reduction.

Claim 3

A method according to claim 1 including the step of collecting particles passing through the screen, and placing the collected particles into an airstream for transportation of the particles towards a point of use.

Claim 5

A method according to claim 5 wherein the speed differential between the serrated surfaces is between about 1:1.5 to about 1: 6.

Claim 6

A method according to claim 5 wherein the step of recycling comprises the steps of positioning the oversize particles adjacent the cylindrical surfaces and substantially concentrically therewith and sweeping the oversize particles in the direction of rotation of the cylindrical surfaces through physical contact between the surfaces and the particles and creation of an airstream adjacent the surfaces, and directing the particles back into the space between the surfaces.

Claim 7

Apparatus for shredding closed cell foam into foam particles having open cells, the apparatus comprising: a housing, a Pair of parallel, spaced-apart shredding rolls defining a gap therebetween, each roll having a substantially circular periphery and a plurality of sawtoothlike serrations on the periphery, drive means rotating the rolls in opposing directions to cause a shredding of the foam passing into the gap, each roll comprising a plurality of axially spaced large and small diameter circular discs having a serrated periphery and wherein the rollers are positioned so that the large diameter discs of the rolls interlace and are opposite small diameter discs of the other roll, means for guiding the foam into the gap, and means for collecting shredded foam particles and removing them from the housing.

Claim 8

Apparatus for shredding closed cell foam into foam particles having open cells, the apparatus comprising: a housing, spaced-apart foam shredding rolls defining a gap therebetween, drive means for rotating the rolls in opposing directions for shredding foam passing through the gap, and a screen mounted to the housing and positioned downstream of the gap for preventing excessively large particles from passing through the screen and for returning the excessively large particles to an upstream end of the gap for recirculation and further size reduction, the screen having first sections extending from a screen center substantially aligned with the gap to a point intermediate the center point and a corresponding end of the screen in the direction of rotation of the adjacent roll, the first sections being substantially concentric with the adjacent roll periphery and spaced therefrom, and second sections between the intermediate point and the adjacent screen end, the second sections being eccentric with respect to the roll peripheries and arranged so that the distance between each roll periphery and the adjacent second screen section increases in the direction of rotation of the rolls.

Claim 9

Apparatus for shredding foam beads into small size, generally ragged foamed particles having open cells, the apparatus comprising: a closed housing, means defining a pair of movable, spaced-apart shredding surfaces having tooth-shaped protrusions arranged transversely to the direction of movement of the surfaces, a screen placed beneath the surfaces and comprising first and second screen halves meeting at a screen center beneath a gap between the surfaces, each screen half further having a first section extending substantially parallel to an adjacent shredding surface away from the screen center, and a second section contiguous with the first section and extending nonparallel with respect to the adjacent shredding surface, at least one of each second section and interior portions of the housing being arranged for guiding shredded particles too large to pass through the screen back to an upstream end of the gap for recirculation of such particles, collection means disposed beneath the screen for collecting the particles and removing them from the housing, and drive means for moving the shredding surfaces with respect to each other.