Pultrusion apparatus

• US 5,716,487 A
• Filed: 06/03/1996
• Issued: 02/10/1998
• Est. Priority Date: 01/10/1995
• Status: Expired due to Term

• Current Assignee: PNC Bank National Association (The PNC Financial Services Group, Inc.)
• Original Assignee: Creative Pultrusions, Inc. (Hill & Smith Plc)
• Inventors: Sumerak, Joseph E.
• Primary Examiner(s): Maki, Steven D.
• Application Number:
  US08/656,778
• Time in Patent Office: 617 Days
• Field of Search: 156/166, 156/180, 156/181, 156/282, 156/311, 156/361, 156/441, 156/498, 156/359, 264/136, 264/137, 264/296, 425/384, 425/392, 425/395, 425/407, 425/509, 425/518, 249/78, 249/80
• US Class Current: 156/359
• CPC Class Codes: B29C 70/525 Component parts, details or accessories; Auxiliary operations

Abstract

A method for producing a pultrusion product having a variable cross-section using a specially adapted temperature controllable pultrusion die includes the steps of pulling reinforcing fibers which have been impregnated with a heat curable thermosetting polymeric resin composition through a temperature controllable die, heating the temperature controllable die to a temperature sufficient to effect curing of the thermosetting resin, cooling the temperature controllable die to a temperature which is sufficiently low to prevent any significant curing of thermosetting resin passing through the pultrusion die, pulling the cured material and a predetermined length of uncured material from the die, reshaping the uncured material, and curing the reshaped material. The reshaping step can be used to provide off-sets, flanges, bosses and the like. The method and associated apparatus of the invention provide a relatively simple and inexpensive way of producing fiber-reinforced thermoset plastics having a variable cross-section.

Claims

1. An apparatus for preparing a fiber-reinforced thermoset article, comprising:

an elongate die having a die cavity about a longitudinal axis therethrough;

means for selectively pulling at least at a first rate of speed and a second rate of speed a continuous material comprised of reinforcing fibers which are impregnated with a heat curable thermosetting resin composition through said die, said second rate of speed being very slow or stopped;

activatable means for heating at least a portion of the entire length of said die to a temperature which is sufficiently high to cause said heat curable thermosetting resin composition in said die to cure, said heating means being activatable to heat said die to transfer heat said material when it is pulled at said first rate of speed through said die; and

activatable means for cooling at least said portion of said die to a temperature which is sufficiently low to prevent said heat curable thermosetting resin composition in said die from curing so that when said continuous material is pulled at said second rate of speed said cooling means is activatable to prevent said die from heating said continuous material to a cure temperature and means for reshaping and curing uncured material which has been pulled from said die.

2. The apparatus of claim 1, wherein said means for reshaping and curing is a pressure molding apparatus having conforming mold parts, and including means for heating said conforming mold parts to a temperature which is sufficiently high to cause said thermosetting resin composition to cure.

3. The apparatus of claim 2, wherein said pressure molding apparatus includes means for cooling said mold parts to a temperature which is sufficiently low to prevent said thermosetting resin composition from curing.

4. The apparatus of claim 3, wherein the pressure molding apparatus is movable along a linear path generally in line with the direction of the longitudinal axis of the die cavity, said pressure molding apparatus acting as an auxiliary gripping/pulling device.

5. The apparatus of claim 2, wherein said pressure molding apparatus includes means for piercing or shearing fibers of said continuous material.

6. The apparatus of claim 1, wherein said die has an outer wall and an inner wall which define said die cavity and the maximum distance from any point on the die inner wall to a point on the outer wall of said die is less than about 1/2 inch.

7. The apparatus of claim 1, wherein said pulling means comprises reciprocating clamp puller means including means for sensing and avoiding clamping onto any portion of pultruded material which has been reshaped.

8. The apparatus of claim 1, wherein said die comprises;

a plurality of die parts which can be securely assembled into an elongate die defining a die cavity, a wall thickness of said die being the perpendicular distance from a point on the die cavity wall to a point on the outer wall of said die, said thickness of said die at any point on the die cavity wall being less than about 1/2 inch.

9. An apparatus as set forth in claim 1, wherein said die comprises a seamless elongate tubular die having an outer wall and an inner wall which defines a die cavity, a wall thickness of said seamless die being the perpendicular distance from a point on the die inner wall to an opposing point on the outer wall of said die, the thickness of said die at any point on the die cavity wall being less than or about 1/2 inch.

10. An apparatus as set forth in claim 1, wherein said die has a wall thickness so as to yield a deformation of no more than 0.002 inch when subjected to an internal outwardly acting pressure of 200 psi.

11. An apparatus for preparing a fiber-reinforced thermoset article, comprising:

an elongate die having a die cavity about a longitudinal axis therethrough;

means for pulling a continuous material comprised of reinforcing fibers which are impregnated with a heat curable thermosetting resin composition through said die;

means for heating at least a portion of the entire length of said die to a temperature which is sufficiently high to cause said heat curable thermosetting resin composition in said die to cure;

means for cooling at least said portion of said die to a temperature which is sufficiently low to prevent said heat curable thermosetting resin composition in said die from curing;

means for reshaping and curing uncured material which has been pulled from said die;

said pulling means comprises reciprocating clamp puller means including means for sensing and avoiding clamping onto any portion of pultruded material which has been reshaped.

12. An apparatus as set forth in claim 11, wherein said die has a wall thickness which is generally conforming to the cross-sectional shape of the die cavity.

13. An apparatus as set forth in claim 11 which includes computer means for controlling the means for pulling, the means for heating and the means for cooling.

14. An apparatus for preparing a fiber-reinforced thermoset article, comprising:

an elongate die having a die cavity about a longitudinal axis therethrough;

a puller for selectively pulling at least at a first rate of speed and a second rate of speed a continuous material comprised of reinforcing fibers which are impregnated with a heat curable thermosetting resin composition through said die, said second rate of speed being very slow or stopped;

a heater for heating at least a portion of the entire length of said die to a temperature which is sufficiently high to cause said the curable thermosetting resin composition in said die to cure, said heater being activatable to heat said die to transfer heat to said material when it is pulled at said first rate of speed through said die; and

a cooling jacket for cooling at least said portion of said die to a temperature which is sufficiently low to prevent said heat curable thermosetting resin composition in said die from curing so that when said continuous material is pulled at said second rate of speed, said cooling jacket is activatable to prevent said die from heating said continuous material to a cure temperature;

a computer for controlling the puller, the heater and the cooling jacket; and

a pressure molding apparatus for reshaping and curing uncured material which has been pulled from said die, said pressure molding apparatus having conforming mold parts, and including a heater for heating said conforming mold parts to a temperature which is sufficiently high to cause said thermosetting resin composition to cure.