Apparatus for and method of manufacturing of preforms having a longitudinal wall with a variable cross section

• US 5,330,342 A
• Filed: 11/20/1992
• Issued: 07/19/1994
• Est. Priority Date: 08/08/1991
• Status: Expired due to Term

• Current Assignee: Ossberger-Turbinenfabrik GmbH
• Original Assignee: Ossberger-Turbinenfabrik GmbH
• Inventors: Linss, Gerhard, Ossberger, Karl-Friedrich
• Primary Examiner(s): Timm, Catherine
• Application Number:
  US07/979,144
• Time in Patent Office: 606 Days
• Field of Search: 264/40.5, 264/40.7, 264/40.1, 264/539, 264/506, 264/537, 264/541, 425/150, 425/532, 425/533, 425/529, 425/174.2
• US Class Current: 425/150
• CPC Class Codes: B29C 2949/3032 having components being injected
• CPC Class Codes: B29C 2949/3041 having components being extruded
• CPC Class Codes: B29C 49/04 Extrusion blow-moulding
• CPC Class Codes: B29C 49/78 Measuring, controlling or regulating
• CPC Class Codes: B29K 2995/0097 Thickness
• CPC Class Codes: B29L 2031/703 Bellows
• CPC Class Codes: F16J 3/041 Non-metallic bellows

Abstract

An apparatus for manufacturing a tube-like preform having a longitudinal wall with a variable cross-section for blow molding of a hollow body from a thermoplastic material, includes a tubular die having a variable exit opening, and a collar die having a recess and movable into engagement with and away from the tubular die, the preform being produced by ejecting of the thermoplastic material from the exit opening of the tubular die into the recess of the collar die while moving tubular die, with controlling a speed of movement of the collar die and a cross-section of the exit opening of the tubular die in such a manner that larger and smaller cross-section of the exit opening correspond to speed rate of the collar die, so that a thickness of the wall of the producible preform changes from peaks to valleys in a wave-like manner to form the variable cross-section of the wall.

Claims

1. An apparatus for manufacturing a tube-like preform having a longitudinal wall with a variable cross-section for flow molding of a hollow body from a thermoplastic material, said apparatus comprising:

a tubular die having an exit opening with a variable cross-section;

a collar die having a recess, said collar die being movable into engagement with and away from said tubular die, the thermoplastic material being injected through said exit opening of said tubular die into said recess of said collar die when said collar die sits on said tubular die, and the preform being manufactured upon movement of said collar die away form said tubular die;

first drive means for moving said collar die into engagement with and away from said tubular die;

second drive means for varying the cross-section of said exit opening of said tubular die;

first control means for controlling operation of said first drive means; and

second control means for controlling operation of said second drive means;

wherein said first control means and said second control means are actuatable during movement of said collar die away from said tubular die, and are operable in accordance with displacement paths of said collar die and said second drive means;

wherein said first control means and said second control means are associated with computer means, constantly operable during movement of said collar die away from said tubular die, for producing the preform, said computer means being connected with storage means containing a program for forming the variable cross-section of the wall of the preform along its entire longitudinal extent in accordance with a displacement path of said collar die when it moves away from said tubular die, whereby a speed of movement of said collar die away from said tubular die, which increases from a zero value, is continuously controlled, and oscillations of larger and smaller cross-sections of said exit opening of said tubular die are controlled in accordance with a continuously controlled speed rate of the movement of said collar die away from said tubular die, so that a thickness of the wall of the produced preform changes from peaks to valleys in a wave-like manner to form the variable cross-section of the wall; and

wherein said first control means comprises a continuously operable first displacement measuring device for determining positions of said collar die and connected with said computer means, said first displacement measuring device comprising an ultrasound position sensor including a movable position indicator-ring magnet, a measuring tube encompassing a measuring wire and associated with an electrical pulse sender and an ultrasound pulse receiver.

2. An apparatus for manufacturing a tube-like preform having a longitudinal wall with a variable cross-section for blow molding of a hollow body from a thermoplastic material, said apparatus comprising:

a tubular die having an exit opening with a variable cross-section;

a collar die having a recess, said collar die being movable into engagement with and away from said tubular die, the thermoplastic material being injected through said exit opening of said tubular die into recess of said collar die when said collar die sits on said tubular die, and the preform being manufactured upon movement of said collar die away form said tubular die;

first drive means for moving said collar die into engagement with and away from said tubular die;

second drive means for varying the cross-section of said exit opening of said tubular die;

first control means for controlling operation of said first drive means; and

second control means for controlling operation of said second drive means;

wherein said first control means and said second control means are actuatable during movement of said collar die away from said tubular die, and are operable in accordance with displacement paths of said collar die and said second drive means;

wherein said first control means and said second control means are associated with computer means, constantly operable during movement of said collar die away from said tubular die, for producing the preform, said computer means being connected with storage means containing the program for forming the variable cross-section of the wall of the preform along its entire longitudinal extent in accordance with a displacement path of said collar die when it moves away from said tubular die, whereby a speed of movement of said collar die away from said tubular die, which increases from a zero value, is continuously controlled and oscillations of larger and smaller cross-sections of said exit opening of said tubular die are controlled in accordance with a continuously controlled speed rate of the movement of said collar die away from said tubular die, so that a thickness of the wall of the produced preform changes from peaks to valleys in a wave-like manner to form the variable cross-section of the wall;

wherein said tubular die includes an axially adjustable die torpedo for changing the cross-section of said exit opening of said tubular die, said second drive means driving said torpedo;

and wherein said second control means comprises a second continuously operable displacement measuring device for determining positions of said second drive means and connected with said computer means, said second displacement measuring device comprising an ultrasound position sensor including a movable position indicator-ring magnet, a measuring tube encompassing a measuring wire and associated with an electrical pulse sender and an ultrasound pulse receiver.

3. An apparatus for manufacturing a tube-like preform having a longitudinal wall with a variable cross-section for blow molding of a hollow body from a thermoplastic material, said apparatus comprising:

a tubular die having an exit opening with a variable cross-section;

a collar die having a recess, said collar die being movable into engagement with and away from said tubular die, the thermoplastic material being injected through said exit opening of said tubular die into said recess of said collar die when said collar die sits on said tubular die, and the preform being manufactured upon movement of said collar die away form said tubular die;

first drive means for moving said collar die into engagement with and away from said tubular die;

second drive means for varying the cross-section of said exit opening of said tubular die;

first control means for controlling operation of said first drive means; and

second control means for controlling operation of said second drive means;

wherein said first control means and said second control means are actuatable during movement of said collar die away from said tubular die, and are operable in accordance with displacement paths of said collar die and said second drive means;

wherein said first control means and said second control means are associated with computer means, constantly operable during movement of said collar die away from said tubular die, for producing the preform, said computer means being connected with storage means containing a program for forming the variable cross-section of the wall of the preform along its entire longitudinal extent in accordance with a displacement path of said collar die when it moves away from said tubular die, whereby a speed of movement of said collar die away from said tubular die, which increases from a zero value, is continuously controlled and oscillations of larger and smaller cross-sections of said exit opening of said tubular die are controlled in accordance with a continuously controlled speed rate of the movement of said collar die away from said tubular die, so that a thickness of the wall of the produced preform changes from peaks to valleys in a wave-like manner to form the variable cross-section of the wall;

and wherein said apparatus further comprises a pressure piston movable along a straight line for pressing the thermoplastic material through said exit opening of said tubular die; and

third drive means for displacing said pressure piston;

third control means for controlling operation of said third drive means for changing a displacement speed of said pressure piston said third control means comprising a third continuously operable displacement measuring device for determining positions of said pressure piston and connected with said computer means, said third displacement measuring device comprising an ultrasound position sensor including a movable position indicator-ring magnet, a measuring tube encompassing a measuring wire and associated with an electrical pulse sender and an ultrasound pulse receiver.

4. An apparatus for manufacturing a tube-like preform having a longitudinal wall with a variable cross-section for blow molding of a bellows from a thermoplastic material, said apparatus comprising:

a tubular die having an exit opening with a variable cross-section;

a collar die having a recess, said collar die being movable into engagement with and away from said tubular die, the thermoplastic material being injected through said exit opening of said tubular die into said recess of said collar die when said collar die sits on said tubular die, and the preform being manufactured upon movement of said collar die away form said tubular die;

first drive means for moving said collar die into engagement with and away from said tubular die;

second drive means for varying the cross-section of said exit opening of said tubular die;

first control means for continuously controlling operation of said first drive means;

second control means for continuously controlling operation of said second drive means; and

computer means for continuously controlling a speed of said first drive means and displacement of said second drive means in accordance with operation of said first control means and said second control means and in accordance with a program, which controls forming the cross-section of the wall of the preform along its entire longitudinal extent in accordance with the displacement path of said collar die when it moves away from said tubular die, in such a manner that oscillations of larger and smaller cross-sections of said exit opening of said tubular die correspond to a continuously controlled speed rate of the movement of said collar die so, that a thickness of the wall of the produced preform changes from peaks to valleys in a wave-like manner to form the variable cross-section of the wall.

5. An apparatus as set forth in claim 4, wherein said controlled oscillating larger and smaller cross-sections of said exit opening, during movement of said collar die away from said tubular die, lead to formation of at least six thickness peaks and thickness valleys in the cross-section of the wall of the manufactured preform.

6. An apparatus according to claim 4, wherein said controlled oscillating larger and smaller cross-sections of said exit opening of said tubular die are controlled in accordance with a straight bevel section.

7. An apparatus according to claim 4, wherein the manufactured preform is used for manufacture of an axle cup of a motor vehicle.