Patent DE-10101823-A1 (DE)
Title: Assembly to cut an extruded compressed wood strand into lengths has a slide for the saws which is moved into the strand movement speed in the cutting station to match the capacity of the extrusion press
Inventor: SCHEDLBAUER KARL
IPC: B30B11/22
Filed: 2001-01-17
Abstract: The saw assembly to cut a strand (14) of compressed wood material into lengths, from an extrusion press, has a slide (1) to carry the saws. Before the saws (11) cut into the material, the slide is moved to bring it up to the speed of material movement out of the extrusion press within a set time span which is shorter than the time taken to move the material into the cutting station, so that the saws are not thrown forward as the leading end of the wood material strand hits the limit stop. A shock absorber on the saw slide, which is independent of the forces, brings the extruded strand into the extended position in a shorter time span than the extrusion speed, and moves the saw slide in the press direction. The sawn sections from the strand, in total, are at least twice as long as the ejection stroke from the extrusion press. Metal components in the extruded wood strand are detected and indicated, before sawing, and the press plunger stroke and/or the extrusion press cycle is interrupted. If the saw slide has not reached the limit cylinder (5) in front of the shock absorber (6), within a given time span while the extruded wood strand is at the limit stop, the slide is advanced by the limit cylinder into its final position. An independent claim is included for a wood strand sawing assembly, with a limit cylinder on the saw slide on the limit stop for the extruded wood strand, with a piston rod through it. Behind it is an adjustable shock absorber with a brake acceleration, where the cylinder stroke is one-eighth to one-third of the total saw cutting length, and the shock absorber has a matching stroke. Preferred Features: The extruded wood strand meets the head section of the limit cylinder, and pushes it inwards, and the shock absorber is moved inwards with a controlled brake acceleration. The saw slide is moved in the press direction with the strand movement speed minus the shock absorber brake acceleration. The limit cylinder has a stroke length of 30-150 mm, to move in and out with its own force. The saw shaft (9) is powered by a flange motor mounted to the rocker plate. The rocker, saw slide and the sawblade housing are of a light metal construction, to reduce the moving mass. The total cutting length of the saws is longer than twice the strand ejection length from the extruder. The movement path of the saw slide is at least 2.2 times the total cutting length and preferably 3.5 times. The force of the limit cylinder is greater than the adjustable residual force of the slide cylinder and the limit cylinder can move the saw slide against it. A metal detector (27) is between the saw unit and the extrusion press, to locate metal material and indicate its presence. The limit cylinder is an oval or flat cylinder, e.g. a Festo (RTM) cylinder. The protective hood (28) over the sawblades has a double-shell structure. The space between the shells is filled with an acoustic insulation material (29) e.g. rock wool or an insulating plastics foam. The inner shell is armored with a wear-resistant plate, using nitriding to give the wear-resistant effect. The rocker (8) is braked by a shock absorber when it is moved into its end position.