Method and apparatus for manufacturing foldable conduit

An apparatus for manufacturing plastic conduit products which have a relatively strong top wall made up of a pair of side walls connected longitudinally at a apex area and having longitudinally extending base ends disposed opposite the apex area and having a flexible base connected adjacent the base ends of the side wall, the manufacturing apparatus comprising:

• means for conveying substantially continuously at least one conduit product top wall;
• means for applying beads of hot, softened plastic material to each of the base ends, the plastic bead applying means including:
• an extruder for plasticizing and extruding plastic material with pressure and heat;
• a manifold for dividing a flow of plasticized material from the extruder to a plurality of applicators, each applicator having an internal bore through which a bead of plastic material is applied adjacent one of the base ends;
• a supplemental heating means disposed adjacent the internal bore for selectively adjusting the viscosity of the plastic material which adjusts a flow rate of the plasticized material therethrough;
• flexible material feeding means for feeding at least one substantially continuous strip of flexible material adjacent the base ends;
• a removable plate assembly including positioning means for selectively positioning a flexible strip relative to the base ends, the positioning means including an upper and a lower plate which are spring biased together, the flexible strip passing between the upper and lower plates;
• a ribbed roller for pressing the flexible strip against the hot plastic bead and the base ends to be bonded therewith, the ribbed roller allowing the flexible strip to assume a wavey, pie crust-like configuration adjacent the hot plastic bead to accomodate thermal deformation of the flexible strip by heat from the hot plastic bead;
• and,
• pulling means for pulling the conduit product to pull the top wall from the conveying means.

An apparatus for manufacturing plastic conduit products which have a relatively strong top wall made up of a pair of side walls connected longitudinally at a apex area and having longitudinally extending base ends disposed opposite the apex area and having a flexible base connected adjacent the base ends of the side wall, the manufacturing apparatus comprising:

• means for conveying substantially continuously at least one conduit product top wall:
• means for applying beads of softened plastic material to each of the base ends;
• a removable plate assembly including:
• positioning means for selectively positioning a flexible strip relative to the top wall, the positioning means includes an upper and a lower plate which are spring biased together, the flexible strip passing between the upper and lower plates, and
• a roller for pressing the flexible strip against the softened plastic bead, the positioning means being disposed adjacent the roller such that the flexible strip is fed through the positioning means and around the roller into contact with the base ends;
• flexible material feeding means for feeding the flexible strip to the positioning means;
• and,
• pulling means for pulling the conduit product to pull the top walls from the conveying means through the removable plate assembly and to pull the flexible strips through the removable plate assembly.

An apparatus for manufacturing a pair of plastic conduit products each of which have a relatively strong top wall made up of a pair of side walls connected longitudinally at a apex area and having longitudinally extending base ends disposed opposite the apex area and having a flexible base connected adjacent the base ends of the side wall, the manufacturing apparatus comprising:

• means for forming and conveying substantially continuously a pair of conduit product top walls, each top wall having a plurality of longitudinally extending rows of outward projecting dimples;
• dimple severing means for severing the outward projecting dimples, the dimple severing means including a severing blade disposed in longitudinal alignment with each dimple row, each severing blade having a generally V-shaped notch disposed generally in line with the corresponding dimple row such that the projections are cut by the V-shaped notch in the blade;
• a flexible material roll support stand including a stationary support, a first arm rotatably mounted on the stationary support, a first spindle being rotatably mounted adjacent a first end of the first rotatable arm, a second spindle being mounted adjacent the other end of the first rotatable arm, and first locking means for selectively locking the first rotatable arm against rotation, and a second arm rotatably mounted on the stationary support, a third spindle rotatably mounted at one end of the second arm, a fourth spindle rotatably mounted at the other end of the second arm, and a second locking means for selectively locking the second rotatable arm against rotation, a first flexible strip roll is mounted on the first spindle, a second flexible strip roll is mounted on the second spindle, a third flexible strip roll is mounted on the third spindle, and a fourth flexible strip roll is mounted on the fourth spindle;
• a first splicing means for selectively splicing a trailing end of the first flexible strip roll with a leading end of the second flexible strip roll and a second splicing means for selectively splicing a trailing end of the third flexible strip roll with a leading end of the fourth flexible strip roll, the first and second splicing means being disposed downstream from the support stand;
• an accumulator means for accumulating a reserve of the first and third flexible strips and for playing out a reserve of the first flexible strip as the first splicing means is splicing first and second rolls and for independently playing out a reserve of the third flexible strip as the second splicing means is splicing the third and fourth rolls, the accumulator being disposed downstream from the first and second splicing means;
• flexible strip perforating means for perforating the flexible strips, the flexible strip perforating means being disposed downstream from the accumulator;
• attaching means for attaching one of the perforated flexible material strips adjacent the base ends of each top wall to form a pair of the conduit products;
• and,
• pulling means for pulling the pair of conduit products to pull the top walls from the conveying means through the attaching means and to pull the flexible strips from the support stand and through the splicing means, the accumulator means, the flexible strip perforating means, and the attaching means.

An apparatus for manufacturing plastic conduit products which have a relatively strong top wall made up of a pair of side walls connected longitudinally at a apex area and having longitudinally extending base ends disposed opposite the apex area and having a flexible base connected adjacent the base ends of the side wall, the manufacturing apparatus comprising:

• means for conveying substantially continuously at least one conduit product top wall;
• attaching means for attaching a strip of flexible material adjacent the base ends of each top wall to form the conduit products;
• flexible material feeding means for feeding at least one substantially continuous strip of flexible material to the attaching means, the flexible strip feeding means including a splicing means for splicing a trailing end of a first flexible material strip with a leading end of a second flexible material strip, the splicing means including:
• means for defining a first guide path for receiving the first flexible strip,
• means for defining a second guide path for receiving the leading end of the second flexible strip,
• a stripper plate having a plurality of spaced guide slots disposed adjacent the guide path defining means,
• a heater means having a plurality of heated portions which are disposable through the guide slots, and
• means for moving the heated portions through the guide slots and into engagement with the first and second flexible strips to fuse the flexible strips together;
• and,
• pulling means for pulling the conduit product to pull the top walls from the conveying means through the attaching means and to pull the flexible strips through the splicing and the attaching means.

An apparatus for manufacturing plastic conduit products which have a relatively strong top wall made up of a pair of side walls connected longitudinally at a apex area and having longitudinally extending base ends disposed opposite the apex area and having a flexible base connected adjacent the base ends of the side wall, the manufacturing apparatus comprising:

• means for conveying substantially continuously at least one conduit product top wall;
• attaching means for attaching a strip of flexible material adjacent the base ends of each top wall to form the conduit products;
• flexible material feeding means for feeding at least one substantially continuous strip of flexible material to the attaching means, the feeding means including flexible strip perforating means for perforating the flexible strip as it is fed to the attaching means, the flexible strip perforating means including a generally rectilinear cross sectioned roller having a plurality of corners around which the flexible strip passes, each of the corners having tangential slots therethrough, and a rotating knife means having knife blades aligned with the tangential slots and disposed to pass through the tangential slots as the corner and the knife blades come into association such that the flexible strip is slit;
• and,
• pulling means for pulling the conduit product to pull the top walls from the conveying means through the attaching means and to pull the flexible strips through the attaching means.

An apparatus for manufacturing plastic conduit products which have at least one relatively strong side wall, the manufacturing apparatus comprising:

• tubular structure forming means for forming substantially continuously a tubular plastic structure which includes at least one side wall, the side wall having a plurality of longitudinally extending rows of outward projecting dimples projecting outward therefrom;
• dimple severing means for severing the outward projecting dimples, the dimple severing means including a severing blade disposed in longitudinal alignment with each dimple row, each severing blade having a generally V-shaped notch disposed generally in line with the corresponding dimple row such that the projections are cut by the V-shaped notch in the blade;
• and,
• pulling means for pulling the conduit product to pull the conduit products from the conveying means through the dimple severing means.

An apparatus for manufacturing plastic conduit products which have a relatively strong, foldable top wall made up of a pair of side walls foldably connected longitudinally at a apex area and having longitudinally extending base ends disposed opposite the apex area and having a flexible base connected adjacent the base ends of the side wall, the manufacturing apparatus comprising:

• tubular structure forming means for forming substantially continuously a tubular structure which includes at least two top walls connected together at their base ends;
• at least a pair of removable splitting blades mounted downstream from the tubular structure forming means and substantially normal to the tubular structure;
• guide means for guiding the tubing structure into the splitting blades such that the splitting blades split the connected base ends;
• at least a pair of dividers, each divider having a relatively sharp upstream edge disposed adjacent and downstream from one of the splitting blades for holding apart the base ends which have been separated by the splitting blades, each divider upstream edge being sufficiently sharp that when a worn splitting blade is removed, the divider upstream edge splits the connected base ends apart until a replacement splitting blade is mounted;
• attaching means for attaching a pair of strips of flexible material, one adjacent the base ends of each top wall to form the conduit products;
• flexible material feeding means for feeding the pair of substantially continuous strips of flexible material to the attaching means;
• and,
• pulling means for folding and pulling the conduit products, the pulling means comprising:
• a first frame,
• a second frame,
• a first pair of belts for receiving one of the top walls therebetween in a folded configuration, the first belt pair including a first belt mounted on the first frame and a second belt mounted on the second frame,
• a second pair of belts for receiving the other top wall therebetween in a folded configuration, the second belt pair including a third belt mounted on the first frame and a fourth belt mounted on the second frame,
• a first rotatable drive wheel operatively connected with the first and third belts for rotating the first and third belts therewith,
• a second rotatable drive wheel operatively connected with the second and fourth belts for rotating the second and fourth belt therewith,
• a flexible drive which drives the first and second wheels, the first and second belts, and the third and fourth belts in opposite directions causing the adjacent portions of the belts to move in the same direction,
• belt adjusting means for adjusting the distance between the first and second frames, adjusting the distance between the first and second drive wheels and adjusting the distance between the first and second belts and the third and fourth belts such that the adjusting means adjusts squeezing of the folded top walls between the first and second belts and the third and fourth belts, and
• tension maintaining means around which the flexible drive wraps for maintaining tension on the flexible drive as the belt adjusting means adjusts the distances between the first and second drive wheels.

An apparatus for manufacturing plastic conduit products which have at least one relatively strong side wall, the manufacturing apparatus comprising:

• tubular structure forming means for forming substantially continuously a tubular plastic structure which includes the at least one side wall, the side wall having a plurality of longitudinally extending rows of outward projecting dimples projecting outward therefrom;
• dimple severing means for severing the outward projecting dimples, the dimple severing means including a severing blade disposed in longitudinal alignment with each dimple row, each severing blade having a notch disposed generally in line with the corresponding dimple row such that the projections are cut by the notch in the blade;
• pulling means for pulling the conduit product from the tubular structure forming means and through the dimple severing means;
• and,
• cut off means disposed downstream from the pulling means for selectively cutting off the conduit product, the cut off means including a non-rotating knife blade for cutting the conduit and a fluid driven cylinder for selectively driving the knife blade linearly through the conduit product.